Morphofunctional interaction of CART peptide and dopaminergic brain neurons

In Wistar rats, after 6 h of sleep deprivation and subsequent 2 h postdeprivation sleep, we found significant changes in optical density of CART peptide in neurons of nucleus accumbens and hypothalamic nucleus arcuatus as well as in processes coming into substantia nigra from nucleus accumbens. The obtained data revealed unidirectional changes of optical density of CART and tyrosine hydroxylase in the studied structures: a decrease after sleep deprivation (p < 0.05) and, on the contrary, an increase after postdeprivation sleep (p < 0.05). Confocal laser microscopy showed morphological connections of CART and dopaminergic neurons and possible colocalization of these both substances in the same neuron at the postdeprivation sleep. In experiments in vitro, after 1 h of incubation of surviving brain sections from the substantia nigra area in the medium with CART peptide there was revealed a rise of optical density of tyrosine hydroxylase in the substantia nigra pars compacta by 55% (p < 0.05). The obtained data indicate an activating effect of CART peptide on brain dopaminergic neurons and its role as a modulator of their functional activity.