Izvestiya of Saratov University.

Chemistry. Biology. Ecology

ISSN 1816-9775 (Print)
ISSN 2541-8971 (Online)


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Russian
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Article

Peculiarities of Modulation by Arginine-vasopressin the Regular and Non-Regular Spike Activity of the Suprahiasmtic Nucleus Neurons

Autors: 
Tkacheva М. А., Samara University
Karyan S. D., Samara University
Inyushkina Е. М., Samara University
Inyushkin А N., Samara University
Abstract: 

The suprachiasmatic nucleus generating biological circadian rhythms in mammals and humans, contains a high proportion of neurons, producing arginine-vasopressin. In in vitro experiments on hypothalamic slices of rats, the comparative analysis of the effect of 20 nM argininevasopressin on the spike activity parameters of neurons with regular (n =23) and irregular (n=28) activity in the suprachiasmatic nucleus was performed. The application of vasopressin induced an increase in the spike frequency in neurons of both groups, but the percentage of cells with irregular activity, responding to the peptide, turned out to be higher: during the administration of vasopressin, firing frequency increased in 64,3% neurons with irregular and 21,7% neurons with regular activity. The responses of neuronal activity were also characterised by a decrease in irregularity of spike generation as reflected in entropy of log distribution of interspike intervals. Vasopressin though did not induce changes in the mutual information between the joined interspike intervals, suggesting a lack of significant effect of the peptide on a degree of information patterning in spike code of cells investigated. The data obtained indicate the ability of arginine-vasopressin to modulate the activity of neurons in the suprachiasmatic nucleus. The primary effect of vasopressin on neurons with irregular activity suggests necessity of intact synaptic afferent inputs for manifestation of the effects. At the same time, respectively weak influence of vasopressin on the activity of cells with regular activity makes unlikely implementation of the peptide effects at the level of own pacemaker mechanisms of spike generation.

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