THE EFFECT OF NEUROPEPTIDE Y ON FUNCTIONAL STATE OF AFFERENT INPUTS FROM ARCUATE NUCLEUS TO THE SUPRACHIASMATIC NUCLEUS OF RAT IN VITRO
In the experiments on sagittal hypothalamic slices of rats with electrophysiological technique of the construction and analysis of the peristimulus time histogram (PSTH), a modulatory effect of 10 nM neuropeptide Y on afferent inputs to the suprachiasmatic nucleus neurons from the hypothalamic arcuate nucleus was studied. The statistically significant responses to the arcuate nucleus stimulation were found in 24 of 54 tested suprachiasmatic neurons. In 8 neurons the response was manifested as a short-latency excitation, in 6 neurons - as a short-latency inhibition. In 12 neurons the complex two- or three-phase responses consisted of different compositions of excitations and inhibitions were recorded. NPY induced qualitative changes in the responses (disappearance of initial or appearing new responses) in 7 neurons initially responded and 1 neuron initially not responded to the arcuate nucleus stimulation. Additionally, in some cases the peptide induced changes in latency and duration of the responses. The obtained data indicate the ability of neuropeptide Y to modulate a functional state of afferent inputs to the suprachiasmatic nucleus circadian oscillator from the hypothalamic arcuate nucleus playing an important role in appetite regulation and metabolism.