Modulating effect of irisin on the functional state of inhibitory afferent inputs to the suprachiasmatic nucleus from the arcuate nucleus

Abstract

In vitro experiments on viable hypothalamic slices of male Wistar rats, the modulating effect of the myokine irisin on the parameters of inhibitory responses of neurons in the suprachiasmatic nucleus to stimulation of the arcuate nucleus was studied. In 25% of cases, applications of 4 nM irisin caused a qualitative change in reactions, expressed in the appearance of a new reaction phase, or in the disappearance of a pre-existing inhibitory phase. In remaining cases, there was a quantitative change in the inhibitory response to stimulation in the form of a decrease in its duration. The reactions were characterized by complete reversibility: 15 minutes after “washing” the slice from irisin with artificial cerebrospinal fluid, the parameters of inhibitory reactions did not differ from the initial ones. The results obtained show that in addition to directly influencing the spike activity of neurons of the suprachiasmatic nucleus, irisin has an indirect effect on the circadian biological clock, modulating the functional state of inhibitory afferent inputs from the region of the arcuate nucleus.