Effects of Bacterial Melanin on Neuronal Spike Activity in the Rat Sensorimotor Cortex
We examined post-stimulation changes in the electrical activity of neurons of the rat
 sensorimotor cortex after intapraperitoneal injections or direct applications of bacterial
 melanin (a strict analog of neuromelanin). Activation of cortical neurons was evoked by highfrequency sti...
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| Опубліковано в: : | Нейрофизиология |
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| Дата: | 2015 |
| Автори: | , , , |
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Інститут фізіології ім. О.О. Богомольця НАН України
2015
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Effects of Bacterial Melanin on Neuronal Spike Activity in the Rat Sensorimotor Cortex / T.R. Petrosyan, O.V. Gevorgyan, A.S. Hovsepyan, A.S. Ter-Markosyan // Нейрофизиология. — 2015. — Т. 47, № 6. — С. 526-532. — Бібліогр.: 18 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860254371934109696 |
|---|---|
| author | Petrosyan, T.R. Gevorgyan, O.V. Hovsepyan, A.S. Ter-Markosyan, A.S. |
| author_facet | Petrosyan, T.R. Gevorgyan, O.V. Hovsepyan, A.S. Ter-Markosyan, A.S. |
| citation_txt | Effects of Bacterial Melanin on Neuronal Spike Activity in the Rat Sensorimotor Cortex / T.R. Petrosyan, O.V. Gevorgyan, A.S. Hovsepyan, A.S. Ter-Markosyan // Нейрофизиология. — 2015. — Т. 47, № 6. — С. 526-532. — Бібліогр.: 18 назв. — англ. |
| collection | DSpace DC |
| container_title | Нейрофизиология |
| description | We examined post-stimulation changes in the electrical activity of neurons of the rat
sensorimotor cortex after intapraperitoneal injections or direct applications of bacterial
melanin (a strict analog of neuromelanin). Activation of cortical neurons was evoked by highfrequency stimulation of the hindlimb peripheral nerves. The patterns of within-stimulation
responses and long-lasting post-stimulation effects were rather similar in both subgroups
(with systemic introductions or direct applications of melanin). Comparison of the results of
previous electrophysiological experiments, where the effects of melanin on electrical activity
generated by neurons of the substantia nigra pars compacta were studied, showed close
similarities of the effects of this agent (mostly activating influence of bacterial melanin with
the predominance of excitatory/facilitatory post-stimulation modifications of spike activity).
The effects of bacterial melanin can contribute to the recovery processes in neurodegenerative diseases.
Ми досліджували постстимуляційні зміни імпульсної активності нейронів сенсомоторної кори щура після внутрішньоочеревинних ін’єкцій або прямих аплікацій бактеріального меланіну (близького аналога нейромеланіну).
Активація кортикальних нейронів викликалася високочастотною стимуляцією периферичних нервів задньої кінцівки. Патерни відповідей у перебігу стимуляції та тривалих постстимуляційних ефектів в обох підгрупах (із
системним уведенням або прямою аплікацією меланіну) виявилися дуже близькими. Порівняння з результатами попередніх електрофізіологічних експериментів, в
яких досліджували впливи меланіну на електричну активність нейронів substantia nigra pars compacta, показало, що спостережувані ефекти (в основному активаційний
вплив бактеріального меланіну з домінуванням збуджувальних/полегшувальних постстимуляційних модифікацій імпульсної активності) були дуже близькими. Ефекти
бактеріального меланіну, ймовірно, можуть бути використані для інтенсифікації процесів відновлення в разі нейродегенеративних захворювань.
|
| first_indexed | 2025-12-07T18:47:27Z |
| format | Article |
| fulltext |
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2015.—T. 47, № 6526
UDC 612.08
T. R. PETROSYAN,1 O. V. GEVORGYAN,2 A. S. HOVSEPYAN,3 and A. S. TER-MARKOSYAN1
EFFECTS OF BACTERIAL MELANIN ON NEURONAL SPIKE ACTIVITY
IN THE RAT SENSORIMOTOR CORTEX
Received May 23, 2014
We examined post-stimulation changes in the electrical activity of neurons of the rat
sensorimotor cortex after intapraperitoneal injections or direct applications of bacterial
melanin (a strict analog of neuromelanin). Activation of cortical neurons was evoked by high-
frequency stimulation of the hindlimb peripheral nerves. The patterns of within-stimulation
responses and long-lasting post-stimulation effects were rather similar in both subgroups
(with systemic introductions or direct applications of melanin). Comparison of the results of
previous electrophysiological experiments, where the effects of melanin on electrical activity
generated by neurons of the substantia nigra pars compacta were studied, showed close
similarities of the effects of this agent (mostly activating influence of bacterial melanin with
the predominance of excitatory/facilitatory post-stimulation modifications of spike activity).
The effects of bacterial melanin can contribute to the recovery processes in neurodegenera-
tive diseases.
Keywords: melanin, sensorimotor cortex neurons, evoked spike activity, potentiation,
depression.
1 Yerevan State Medical University, Republic of Armenia.
2 Institute of Physiology of the NAS of Armenia, Yerevan, Republic of
Armenia.
3 SPC “Armbiotechnology” of the NAS of Armenia, Yerevan, Republic of
Armenia.
Correspondence should be addressed to T. R. Petrosyan (tigpetrosyan@mail.
ru).
INTRODUCTION
Many types of neural cells contain neuromelanins
(NMs); the level of the latter is especially high in
neurons of the substantia nigra (NS). As was reported,
NMs are natural antioxidants capable of considerably
suppressing lipid peroxidase [1]. The oxidative path-
way of dopamine metabolism in the human brain leads
to the formation of NM deposits in the cytoplasm
of nigro-striatal dopaminergic neurons. There are
data of that NM significantly contributes to the
neurodegenerative processes underlying Parkinson’s
disease (PD) but the respective information is still
controversial. Effects of melanin-concentrating
hormone (MCH) and their correlation with memory
retention following amnestic effects induced by NG-
nitro-L-arginine (L-NOARG) have been studied; it
was demonstrated that L- NOARG does not block
potentiation effects induced by the above peptide [2].
An increase in the level of redox-active iron (free Fe2+
form) in association with NM has been revealed in
the SN of patients with PD [3]. According to the cited
authors, most extensive degeneration of dopamin-
ergic neurons in patients with PD was observied in
a subpopulation of neuro melanin-(NM-)containing
neurons of the pars compacta (pc) of the SN. The redox
activity of NM aggregates was studied in a group of
patients with PD. A statistically significant reduction
(–70%) in the number of NM-containing neurons
and an increased content of non-heme iron (Fe3+),
which contribute to oxidative stress and intraneuronal
damage, were found in these subjects. Samples from
the lateral hypothalamic area (LH) showed that MCH
inhibits synaptic activity of both glutamatergic and
GABAergic neurons [4].
A melanin-synthesizing s t ra in of Bacil lus
thuringiensis with a high intensity of pigment
synthesis was obtained in the Armenian Institute of
Biotechnology [5]. This allowed researchers to test
the effects of BM, i.e., an agent nearly completely
similar to NM, in experiments on CNS neurons.
Bacterial melanin has been tested in a few series of
experiments as a neuroprotector capable of enhancing
motor recovery after CNS lesions [6]. Effects of BM
on dopaminergic neurons in the SNpc were also tested;
high-frequency stimulation of the caudate-putamen
was used in these experiments [7]. The results
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2015.—T. 47, № 6 527
EFFECTS OF BACTERIAL MELANIN ON NEURONAL SPIKE ACTIVITY
indicated that BM applications modulate electrical
activity of SNpc dopaminergic neurons, and excitatory
post-stimulation effects prevail over the inhibitory
responses.
In the current study, we examined the influences of
BM on spike activity of neurons of the sensorimotor
cortex (SMC); the effects of systemic (intraperitoneal,
i.p.) injections of BM and its direct applications to the
cortex were compared.
METHODS
Experiments were carried out on 12 mongrel albino
male rats (200–300 g). They were housed in wire mesh
cages in a room lighted at the 12/12 h light/dark cycle
with the temperature set at 22°C. Testing was done
during a light portion of the cycle.
During the experiments, rats were immobilized
with 1% dithylinum solution (25 mg/kg; i.p.);
mechanical ventilation was applied. The head of
the experimental animal was fixed in a stereotaxic
apparatus, and the SMC region was opened
(3 mm lateral from the midline and 3 mm posterior
from the bregma). The region corresponded to the
representation of the contralateral hindlimb [8]. A
stereotaxically oriented glass microelectrode (tip
diameter 1-2 µm) filled with 2 M NaCl solution was
inserted for a depth of 250 to 1800 µm; spike activities
of single pyramidal neurons or cortical interneurons
were recorded. Single or high-frequency (HF)
stimulation (duration 1.0 sec, frequency 100 sec–1)
was applied to peripheral nerves of the hindlimb
(mixed, n. ischiadicus, I; flexor, n. peroneus comm.,
P, or extensor, n. gastrocnemius, G). Modifications of
spike activity in the form of post-tetanic potentiation
(PTP) and depression (PTD) after HF stimulation were
examined; the latency, expressiveness, and duration of
these modifications were measured using a computer.
Extracellular neuronal activity was recorded for rather
long periods (2–3 h).
Data Analysis. A special computer software
developed by V. Kamenetsky was used. It provided
on-line selection of spikes based on amplitude
discrimination. The program displayed peri-stimulation
time histograms (PSTHs) of interspike intervals (ISIs).
Parts of the PSTHs exceeding the M ± 2 s.d. limits
were calculated. This procedure was repeated until the
M and s.d. values were stabilized (differences became
smaller than 2%). The final sampling was considered
a tonic post-stimulation activity of the examined
neuron. The conformity of distributions to the normal,
Poisson, or uniform law was estimated. Depending on
the distribution type, the significance of differences
(exceeding the M ± 2 s.d. limits in the PSTHs) was
estimated using the adequate criteria. The significance
(P) of the difference between background and tonic
post-stimulation activities was estimated by the two-
side Student’s t- test. Cumulative curves were plotted
for the background and tonic activity. The least-square
method was used to determine the slope of lines in
curve plotting [9].
Animals of one subgroup (n = 6) were subjected
to direct BM application to the cortex. Continuous
irrigation of the cortical surface within the SMC
registration area was performed with a special device
with a tube attached to a vial with BM solution
(0.6 mg/ml) to maintain a constant BM level within the
recording area. In another animal subgroup (n = 6), the
BM solution was systemically (i.p.) injected at a rate
6 mg/ml (170 mg/kg) 15 min after immobilization.
RESULTS
In most examined SMC neurons, primary (early)
responses to single stimulations of the hindlimb
peripheral nerves looked as a single spike or a short
burst of spikes. As such primary responses, we
considered significant changes in the background
spiking of SMC neurons observed within 9-msec-
long time intervals after peripheral nerve stimulations
(Fig. 1A). More rarely, primary responses to single
stimulations were poorly manifested at the stimulation
intensities used.
At 1-sec-long HF stimulation of the peripheral
nerves, typical changes in spiking of SMC neurons
looked as significant increases in the discharge
frequency within the period of nerve stimulation
(tetanic potentiation, TP) followed by later long-
lasting facilitation of spike activity (long-lasting
posttetanic potentiation, PTP) (Fig. 1). In more rare
cases, changes in spike activity of cortical neurons
within the period of repetitive HF (100 sec–1)
stimulations of the nerves looked as suppression of
background spiking (tetanic depression, TD) followed
by later long-lasting post-stimulation modifications,
PTP or posttetanic depression (PTD). Thus, in general,
modifications in spike activity of SMC neurons related
to HF stimulations of the hindlimb nerves could be
classified as four combinations of the effects, purely
facilitatory (TP + PTP), purely inhibitory (TD + PTD),
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2015.—T. 47, № 6528
T. R. PETROSYAN, O. V. GEVORGYAN, A. S. HOVSEPYAN, and A. S. TER-MARKOSYAN
35
35
35
3570
70
25
50
70
70
20
40
0
0
50
200 400 600
msec
msec
0 50 msec
0 200 400 600 msec
0
1
1
1
I
P
G
A B
2
2
2
50 100 msec
0 200 400 600 msec
59
29.5
26.5
–25 25 50 msec0
28
56
53
G
P
I
F i g. 1. Peristimulus histograms of responses of two sensorimotor
cortex neurons (A, B) to single (A, 1) and repetitive high-frequency
(A, 2; B) stimulations of the peripheral hindlimb nerves observed
in the control (with no application/injection of bacterial melanin).
I, P, and G are nn. ishiadicus, peroneus comm., and gastrocnemius,
respectively. High-frequency stimulation, 1.0-sec-long trains, 100
sec–1. Bin width: 1 msec (A, 1), 4 msec (A, 2), and 500 msec (B).
Abscissa) Time, msec in A and sec in B; ordinate) spike frequency
in a bin, sec–1.
Р и с. 1. Перистимульні гістограми відповідей двох нейронів
сенсомоторної кори (А, В) на поодиноку (А, 1) та серійну
високочастотну (А, 2; В) стимуляцію периферичних нервів
задньої кінцівки в контролі, без дії бактеріального меланіну.
or mixed (TP + PTD or TD + PTP).
It should be emphasized that long-lasting facilitation
of spiking of SMC neurons was much more clearly
manifested in the cases of stimulations of either a
common nerve trunk (I) or its branching supplying
the flexor hindlimb muscles (P). Under conditions of
HF stimulation of the extensor muscle nerve (G), PTP
was either much less intense (shorter and weaker) or
practically absent at all, and only short-lasting TP was
observed in such cases (Fig. 1B).
Both direct application of BM on the SMC surface
and systemic (i.v.) introduction of this agent resulted
in sustained increases in impulse activity of a great
majority of the examined cortical neurons. Tetanic
stimulation-related modifications of spiking of these
neurons were analyzed in detail in 109 units under
conditions of i.v. injections of BM (Fig. 3) and in
106 cells under conditions of direct application of the
latter (Fig. 2).
The patterns of HF nerve stimulation-induced
modifications of spike activity of SMC neurons
surface and of i.v. injections of BM are illustrated by
Table 1.
As can be easily seen, both modes of PM application
(systemic and direct) provided clear increases in the
proportions of facilitatory modifications of spike
activity of SMC neurons related to HF stimulations
of the hindlimb nerves. Under the action of BM,
the number of pure inhibitory stimulation-related
modifications (TD + PTD) decreased considerably.
In the case of i.p. BM injections, a drop was nearly
twofold. At the same time, the proportions of pure
excitatory effects (TP + PTP), which were observed
before BM applications in less than one third of the
neurons, tended to reach half of the total number of
examined SMC neurons under conditions of action of
this agent.
sec–1
sec–1
sec–1
sec–1
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2015.—T. 47, № 6 529
EFFECTS OF BACTERIAL MELANIN ON NEURONAL SPIKE ACTIVITY
sec–1 sec–1
55
27.5
10
20
28
56
I
P
G
2525
25
12.5
49
10
20
24.5
5050 secsec 00
G 26'
I 18'
P
A B
F i g. 2. Spike activity of two neurons (A, B) of the sensorimotor cortex; responses to high-frequency stimulation of the hindlimb nerves
and long-lasting modifications of the activity under conditions of direct application of bacterial melanin to the cortical surface. Time after
beginning of application, min, is shown above the peristimulus histograms. Other designations are similar to those in Fig. 1.
Р и с. 2. Імпульсна активність двох нейронів сенсомоторної кори (А, В): відповіді на високочастотну стимуляцію нервів задньої
кінцівки та тривалі модифікації активності в умовах прямої аплікації бактеріального меланіну на поверхню кори.
sec–1 sec–1
50
25
25
50
20
19
38
G 5'
G 42'
P 20'
I 10'
I 20'
25 2550 50sec sec0 0
A B
P 45'
50
54
25
27
F i g. 3. Spike activity of two neurons of the sensorimotor cortex (A, B): responses to high-frequency stimulation of the hindlimb nerves
and long-lasting modifications of the activity under conditions of systemic (i.v.) injections of bacterial melanin. Designations are similar
to those in Fig. 2.
Р и с. 3. Імпульсна активність двох нейронів сенсомоторної кори (А, В): відповіді на високочастотну стимуляцію нервів задньої
кінцівки та тривалі модифікації активності в умовах системного (внутрішньовенного) введення бактеріального меланіну.
DISCUSSION
One of the unique properties of melanins is their ability
to successfully cross the blood–brain barrier (BBB)
[10]. The mechanism of this aspect of permeability
of the BBB is not known. This property facilitates
the transport of (NM and also of BM) from the
blood into the brain parenchyma. We tested different
concentrations of BM in our previous experiments, and
the pharmacokinetic profile of BM has been studied.
Bacterial melanin is enzymatically stable in the blood
and brain parenchyma. It demonstrates the saturable
transport across the BBB and selectively reaches
certain targets in the CNS. Circulating BM enters all
regions of the CNS, but its uptake is higher in the
lumbar spinal cord, thalamus, hypothalamus, and SN.
The primary goal of our study was to compare
the obtained results with the data from an
electrophysiological study where effects of BM on
SNpc dopaminergic neurons were examined. The
effects of BM on these neurons were found to be
predominantly excitatory. Such activating effect
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2015.—T. 47, № 6530
T. R. PETROSYAN, O. V. GEVORGYAN, A. S. HOVSEPYAN, and A. S. TER-MARKOSYAN
could be a contributing factor in the process of motor
recovery after destruction of dopaminergic neurons.
The advantage of the present study was that the effects
of direct application of BM on superficial cortical
neurons could be observed.
In experiments of SNpc neurons, we used only
systemic (i.p.) injections of BM because its direct
application was impossible in such in vivo study.
It was also interesting to compare the respective
modifications of the responses in SNpc and
cortical (SMC) neurons. For i.p. injections, the
concentration (6 mg/ml, 170 mg/kg) similar to that
in the above-mentioned experiments was selected.
This concentration was used in all previous studies
with BM and has been proven to be rather effective
and, at the same time, nontoxic. Selection of the BM
concentration for direct application was based on the
pharmacokinetic profile of BM [11]. The tenfold-
diluted concentration of BM was chosen for direct
application.
LTP was shown to be a specific phenomenon not only
in the hippocampus where it has been studied thoroughly.
As is supposed, this modification is involved directly in
the process of formation of short-term memory. It is also
manifested in other brain structures (in the visual striatal
cortex [12] and in synapses formed by the inferior
colliculi brachia neurons in the medial geniculate body
[13]). Studies of induced spike activity in SMC neurons
showed that induction of long-time depression (LTD) is
possible in this case. This phenomenon might be associ-
ated with decrease in the dendritic length and density in
layers III and V of the SMC [14-16]. The same authors
have also studied skilled learning-induced potentiation
in the rat sensorimotor cortex as an example of the tran-
sient form of behavioral LTP [17]. Long-term depression
and depotentiation in the SMC of freely moving rats was
registered by Frog et al. [18]. Recording of electrical ac-
tivity from superficial cortical neurons is a route to ex-
amine an immediate action of the substance (BM), and
such technique is advantageous over registration of ac-
tivity from deeply located neurons. In responses obtained
after both i.p. injection or direct application of BM, an
increased proportion of neurons with TP was observed,
compared to the effects registered before the BM action.
The overall percentage of PTP-like post-effects also in-
creased. Thus higher proportions of facilitatory effects
(TD-PTP and TP-PTP) were found after direct applica-
tions of BM.
Data of this and previous studies correlate well.
Such a correlation confirms the potentiating action of
BM on central neurons (at least, on their significant
part).
Increased electrical activity of neurons can support
the process of motor recovery after injuring influenc-
es on these neurons. In behavioral experiments with
operantly conditioned rats, enhanced recovery of the
limb movements and of the operant conditioned reflex
was observed after SMC ablations in animals treated
with rather small BM amounts. Intraperitoneal injec-
tion proved to be sufficiently effective; the respective
effects were induced very rapidly and persisted for a
longer period (2-3 h) than those after direct applica-
tions; it is important that all such effects demonstrated
an identical pattern.
Bacterial melanin has a clear neuroregenerative
action; it stimulates axonal sprouting and supports
neuronal viability. Probably, these effects of BM
provide the facilitation of motor recovery in rats
T a b l e 1. Number of neurons with different types of modifications of spike activity induced by high-frequency stimulation
of hindlimb peripheral nerves before applications/injections of bacterial melanin and under the action of the latter
Т а б л и ц я 1. Кількість нейронів з різними типами модифікацій імпульсної активності, індукованих високочастотною
стимуляцією периферичних нервів задньої кінцівки, перед аплікаціями/ін’єкціями бактеріального меланіну та в умовах
його дії
Type of the effects
Groups
i.p. injection direct application
pre-inject. post-inject. pre-appl. post-appl.
Inhibitory, TD + PTD 21 (19.3%) 11 (10.1%) 16 (15.1%) 10 (9.4%)
Mixed, TD + PTP 34 (31.2%) 19 (17.4%) 29 (27.4%) 21 (19.8%)
Mixed, TP + PTD 23 (21.1%) 32 (29.4%) 29 (27.4%) 27 (25.5%)
Facilitatory, TP + PTP 32 (29.4%) 47 (43.1%) 32 (30.2%) 48 (45.3%)
Total number of examined neurons 109 109 106 106
Footnotes: normalized numbers, %, of neurons with one type of HF stimulation-related modifications or another are shown in parentheses;
TD and TP are tetanic depression and potentiation; PTD and PTP are long-lasting post-tetanic depression and potentiation, respectively.
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2015.—T. 47, № 6 531
EFFECTS OF BACTERIAL MELANIN ON NEURONAL SPIKE ACTIVITY
REFERENCES
1. T. Wilczok, K. Stepien, A. Dzierzega-Lecznar, et al.,
“Model neuromelanins as antioxidative agents during lipid
peroxidation,” Neurotox. Res., 1, No. 2, 141-147 (1999).
2. M. Varas, M. Perez, M.E. Mouzon, and S. R. de Barioglio,
“Melanin concentrating hormone, hippocampal nitric
oxide levels and memory retention,” Peptides, 23, No. 12,
2213-2221 (2002).
3. B. A. Faucheux, M. E. Martin, C. Beaumont, et al.,
“Neuromelanin associated redox-active iron is increased in
the substantia nigra of patients with Parkinson’s disease,” J.
Neurochem., 86, No. 5, 1142-1148 (2003).
4. A. A. Galoyan, J. S. Sarkissian, T. K. Kipriyan, et al.,
“Protective effect of a new hypothalamic peptide against cobra
venom and trauma induced neuronal injury,” Neurochem. Res.,
26, 1023-1038 (2001).
5. A. E. Aghajanyan, A. A. Hambardzumyan, A. S. Hovsepyan,
et al . , “Isolation, purif ication and physicochemical
characterization of water-soluble Bacillus thuringiensis
melani,” Pigment Cell Res., 18, No. 2, 130-135 (2005).
6. M. H. Monfils and G. C. Teskey, “Skilled-learning - induced
potentiation in rat sensorimotor cortex: a transient form
of behavioral long-term potentiation,” Neuroscience, 125,
No. 2, 329-336 (2004).
7. T. R Petrosyan, V. A. Chavushyan, and A. S. Hovsepyan,
“Bacterial melanin increases electrical activity of neurons in
substantia nigra pars compacta,” J. Neural Transm., 121, 259-
265 (2014).
8. Y. Komatsu, K. Toyama, J. Maeda, and H. Sakaguchi, “Long
term potentiation investigated in a slice preparation of striate
cortex of young kittens,” Neurosci. Lett., 26, 269-274 (1981).
9. R. M. Sulkhanyan and T. S. Khachatryan, “Comparison of
the protection against neuronal injury by hypothalamic pepti-
des and by dexamethasone,” Neurochem. Res., 25, 1567-1578
(2000).
10. D. L. Berliner, R. L. Erwin, and D. R. McGee, “Methods of
treating Parkinson’s disease using melanin,” US Patent 5, 210,
076 A (1993).
11. T. R. Petrosyan and A. S. Hovsepyan, “Bacterial melanin
crosses the blood–brain barrier in rat experimental model,”
Fluids Barriers CNS, 11, No. 20, 1-7 (2014).
12. D. J. Froc, C. A. Capman, C. Trepel, and R. J. Racine, “Long-
term depression and depotentiation in the sensorimotor
cortex of freely moving rat,” J. Neurosci., 20, No. 1, 438-445
(2000).
13. R. A. Gerren and N. M. Weinberger, “Long term potentia-
tion in the magnocellular medial geniculate nucleus of
anesthetized cat,” Brain Res., 265, 138-142 (1983).
14. O.V. Gevorkyan, “Neuronal activity of sensorimotor cortex
on the mesemcephalic reticular formation stimulation,” Biol.
J. Armenia, 40, No. 12, 993-997 (1987).
15. O. V. Gevorkyan, I. B. Meliksetyan, A. S. Ovsepyan, and
A. S. Sagiyan, “Effects of BT-melanin on recovery of
operant conditioned reflexes in rats after ablation of the
sensorimotor cortex,” Neurosci. Behav. Physiol., 37, No. 5,
471-476 (2007).
16. S. P. Hicks and C. I. D’Amato, “Locating corticospinal neu-
rons by retrograde axonal transport of horseradish per-
oxidase,” Exp. Neurol., 56, 410-420 (1977).
after SMC damage (the effect mentioned above).
Augmentation of neuronal activity in the cortex is,
supposedly, another supporting factor that enhances
motor recovery.
Animals were maintained and handled in accordance with
the institutional guidelines and national and international
laws and policies (EEC Council Directive 86/609, OJ L 358,
1, December 12, 1987; NIH Guide for the Care and Use of
Laboratory Animals, NIH Publication No. 86–23, 1985).
The authors, T. R. Petrosyan, O. V. Gevorgyan,
A. S. Hovsepyan, and A. S. Ter-Markosyan, confirm that they
have no conflict of interest with any organization or person
that may be related to this study; there was also no conflict of
interest in interrelations between the authors.
Т. Р. Петросян1. О. В. Геворгян2, А. С. Овсепян3, А. С. Тер-
Маркосян1
ВПЛИВИ БАКТЕРІАЛЬНОГО МЕЛАНІНУ НА
АКТИВНІСТЬ НЕЙРОНІВ У СЕНСОМОТОРНІЙ КОРІ
ЩУРА
1 Єреванський державний медичний університет
(Республіка Вірменія).
2 Інститут фізіології Національної Академії наук Вірменії,
Єреван (Республіка Вірменія).
3 СПЦ «Армбіотехнологія» Національної Академії наук
Вірменії, Єреван (Республіка Вірменія).
Р е з ю м е
Ми досліджували постстимуляційні зміни імпульсної ак-
тивності нейронів сенсомоторної кори щура після вну-
трішньоочеревинних ін’єкцій або прямих аплікацій бак-
теріального меланіну (близького аналога нейромеланіну).
Активація кортикальних нейронів викликалася високо-
частотною стимуляцією периферичних нервів задньої кін-
цівки. Патерни відповідей у перебігу стимуляції та три-
валих постстимуляційних ефектів в обох підгрупах (із
системним уведенням або прямою аплікацією мелані-
ну) виявилися дуже близькими. Порівняння з результа-
тами попередніх електрофізіологічних експериментів, в
яких досліджували впливи меланіну на електричну ак-
тивність нейронів substantia nigra pars compacta, показа-
ло, що спостережувані ефекти (в основному активаційний
вплив бактеріального меланіну з домінуванням збуджу-
вальних/полегшувальних постстимуляційних модифіка-
цій імпульсної активності) були дуже близькими. Ефекти
бактеріального меланіну, ймовірно, можуть бути викорис-
тані для інтенсифікації процесів відновлення в разі ней-
родегенеративних захворювань.
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2015.—T. 47, № 6532
T. R. PETROSYAN, O. V. GEVORGYAN, A. S. HOVSEPYAN, and A. S. TER-MARKOSYAN
17. A. A. Galoyan, J. S. Sarkissian, T. K. Kipriyan, et al.,
“Melanin concentrating hormone depresses synaptic acti-
vity of glutamate and GABA neurons from rat lateral
hypothalamus,” J. Physiol., 15, No. 533, 237-252 (2001).
18. M. H. Monfils and G. C. Teskey, “Induction of long-term
depression is associated with decreased dendritic length
and spine density in layers III and V of sensoromotor
neocortex,” Synapse, 53, No. 2, 114-121 (2004).
|
| id | nasplib_isofts_kiev_ua-123456789-148221 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 0028-2561 |
| language | English |
| last_indexed | 2025-12-07T18:47:27Z |
| publishDate | 2015 |
| publisher | Інститут фізіології ім. О.О. Богомольця НАН України |
| record_format | dspace |
| spelling | Petrosyan, T.R. Gevorgyan, O.V. Hovsepyan, A.S. Ter-Markosyan, A.S. 2019-02-17T18:04:45Z 2019-02-17T18:04:45Z 2015 Effects of Bacterial Melanin on Neuronal Spike Activity in the Rat Sensorimotor Cortex / T.R. Petrosyan, O.V. Gevorgyan, A.S. Hovsepyan, A.S. Ter-Markosyan // Нейрофизиология. — 2015. — Т. 47, № 6. — С. 526-532. — Бібліогр.: 18 назв. — англ. 0028-2561 https://nasplib.isofts.kiev.ua/handle/123456789/148221 612.08 We examined post-stimulation changes in the electrical activity of neurons of the rat
 sensorimotor cortex after intapraperitoneal injections or direct applications of bacterial
 melanin (a strict analog of neuromelanin). Activation of cortical neurons was evoked by highfrequency stimulation of the hindlimb peripheral nerves. The patterns of within-stimulation
 responses and long-lasting post-stimulation effects were rather similar in both subgroups
 (with systemic introductions or direct applications of melanin). Comparison of the results of
 previous electrophysiological experiments, where the effects of melanin on electrical activity
 generated by neurons of the substantia nigra pars compacta were studied, showed close
 similarities of the effects of this agent (mostly activating influence of bacterial melanin with
 the predominance of excitatory/facilitatory post-stimulation modifications of spike activity).
 The effects of bacterial melanin can contribute to the recovery processes in neurodegenerative diseases. Ми досліджували постстимуляційні зміни імпульсної активності нейронів сенсомоторної кори щура після внутрішньоочеревинних ін’єкцій або прямих аплікацій бактеріального меланіну (близького аналога нейромеланіну).
 Активація кортикальних нейронів викликалася високочастотною стимуляцією периферичних нервів задньої кінцівки. Патерни відповідей у перебігу стимуляції та тривалих постстимуляційних ефектів в обох підгрупах (із
 системним уведенням або прямою аплікацією меланіну) виявилися дуже близькими. Порівняння з результатами попередніх електрофізіологічних експериментів, в
 яких досліджували впливи меланіну на електричну активність нейронів substantia nigra pars compacta, показало, що спостережувані ефекти (в основному активаційний
 вплив бактеріального меланіну з домінуванням збуджувальних/полегшувальних постстимуляційних модифікацій імпульсної активності) були дуже близькими. Ефекти
 бактеріального меланіну, ймовірно, можуть бути використані для інтенсифікації процесів відновлення в разі нейродегенеративних захворювань. en Інститут фізіології ім. О.О. Богомольця НАН України Нейрофизиология Effects of Bacterial Melanin on Neuronal Spike Activity in the Rat Sensorimotor Cortex Впливи бактеріального меланіну на активність нейронів у сенсомоторній корі щура Article published earlier |
| spellingShingle | Effects of Bacterial Melanin on Neuronal Spike Activity in the Rat Sensorimotor Cortex Petrosyan, T.R. Gevorgyan, O.V. Hovsepyan, A.S. Ter-Markosyan, A.S. |
| title | Effects of Bacterial Melanin on Neuronal Spike Activity in the Rat Sensorimotor Cortex |
| title_alt | Впливи бактеріального меланіну на активність нейронів у сенсомоторній корі щура |
| title_full | Effects of Bacterial Melanin on Neuronal Spike Activity in the Rat Sensorimotor Cortex |
| title_fullStr | Effects of Bacterial Melanin on Neuronal Spike Activity in the Rat Sensorimotor Cortex |
| title_full_unstemmed | Effects of Bacterial Melanin on Neuronal Spike Activity in the Rat Sensorimotor Cortex |
| title_short | Effects of Bacterial Melanin on Neuronal Spike Activity in the Rat Sensorimotor Cortex |
| title_sort | effects of bacterial melanin on neuronal spike activity in the rat sensorimotor cortex |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/148221 |
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