A. N. Inyushkin, A. Yu. Sharafutdinova, E. M. Inyushkina, A. A. Inyushkin
{"title":"The Effects of Ghrelin on Spike Activity of the Suprachiasmatic Nucleus Neurones of the Rat","authors":"A. N. Inyushkin, A. Yu. Sharafutdinova, E. M. Inyushkina, A. A. Inyushkin","doi":"10.1134/s0022093024030189","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>In one of the most important non-photic mechanisms of the\ncircadian biological clock synchronization of the hypothalamus suprachiasmatic\nnucleus with environmental geophysical 24 h rhythm, information\non feeding schedule, composition and calorie content of food is\nused. Hormone ghrelin, a product of the neuroendocrine oxyntic cells\nof the gastric mucosa to be a signal molecule within this mechanism.\nIn experiments on sagittal hypothalamic slices of male Wistar rats,\nthe effects of 25 nM ghrelin on spike activity and parameters of\nspike information coding were investigated. Application of ghrelin\ninduced an increase in spike frequency and a decrease in entropy\nof interspike interval distribution in 32.1% of the neurones recorded.\nIn 29.6% of the cells, opposite responses in the form of a reduction\nof activity and an increase in the entropy of interspike interval\ndistribution were observed. Parameters of spike activity of the\nreminder 38.3% neurones of the suprachiasmatic nucleus did not change.\nThe observed responses of the entropy of interspike interval distribution\nindicate the appropriate changes in a degree of irregularity of\ninterspike interval induced by ghrelin. Application of selective\nhigh-affinity antagonist of GHS-R1a receptor, JMV 2959 (100 nM)\ndid not induce responses of the investigated parameters of spike\nactivity but completely prevented changes of both, spike frequency and\nentropy of interspike interval distribution observed in the presence\nof ghrelin. The obtained data show that hormone ghrelin by a direct\ninfluence on the suprachiasmatic nucleus in vitro modulates the activity\nlevel and spike code of relatively numerous population of neurones\nof the nucleus, wherein the effects of ghrelin are mediated by GHS-R1a\nreceptors. The results of the current study provide additional evidence\nin favour of the hypothesis on the involvement of ghrelin in mechanisms\nof non-photic entrainment of the circadian biological clock in accordance\nwith severity of food motivation and level of metabolism.</p>","PeriodicalId":15805,"journal":{"name":"Journal of Evolutionary Biochemistry and Physiology","volume":"5 1","pages":""},"PeriodicalIF":0.6000,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Evolutionary Biochemistry and Physiology","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1134/s0022093024030189","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
In one of the most important non-photic mechanisms of the
circadian biological clock synchronization of the hypothalamus suprachiasmatic
nucleus with environmental geophysical 24 h rhythm, information
on feeding schedule, composition and calorie content of food is
used. Hormone ghrelin, a product of the neuroendocrine oxyntic cells
of the gastric mucosa to be a signal molecule within this mechanism.
In experiments on sagittal hypothalamic slices of male Wistar rats,
the effects of 25 nM ghrelin on spike activity and parameters of
spike information coding were investigated. Application of ghrelin
induced an increase in spike frequency and a decrease in entropy
of interspike interval distribution in 32.1% of the neurones recorded.
In 29.6% of the cells, opposite responses in the form of a reduction
of activity and an increase in the entropy of interspike interval
distribution were observed. Parameters of spike activity of the
reminder 38.3% neurones of the suprachiasmatic nucleus did not change.
The observed responses of the entropy of interspike interval distribution
indicate the appropriate changes in a degree of irregularity of
interspike interval induced by ghrelin. Application of selective
high-affinity antagonist of GHS-R1a receptor, JMV 2959 (100 nM)
did not induce responses of the investigated parameters of spike
activity but completely prevented changes of both, spike frequency and
entropy of interspike interval distribution observed in the presence
of ghrelin. The obtained data show that hormone ghrelin by a direct
influence on the suprachiasmatic nucleus in vitro modulates the activity
level and spike code of relatively numerous population of neurones
of the nucleus, wherein the effects of ghrelin are mediated by GHS-R1a
receptors. The results of the current study provide additional evidence
in favour of the hypothesis on the involvement of ghrelin in mechanisms
of non-photic entrainment of the circadian biological clock in accordance
with severity of food motivation and level of metabolism.
期刊介绍：
Journal of Evolutionary Biochemistry and Physiology publishes original experimental and theoretical and review articles related to evolution of the main forms of metabolism in connection with life origin; comparative and ontogenetic physiology and biochemistry, biochemical evolution of animal world; as well as evolution of functions; morphology, pharmacology, pathophysiology and ecological physiology. The journal welcomes manuscripts from all countries in the English or Russian language.
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