[Response of neurons of the ventro- and dorsomedial nuclei of the hypothalamus to biologically heterogeneous stimuli].

Unit activity in ventro- and dorsomedial hypothalamic nuclei recorded extracellulary in nonanaesthetized rabbits was evoked by acoustic clicks or electrocutaneous nociceptive and innocuous stimuli. The majority of units of the dorsomedial hypothalamus was inhibited by nociceptive stimulation and was excited by innocuous one. In contrast, units in the ventro-medial hypothalamus reduced their discharges in response to innocuous stimuli and augmented them in response to nociceptive stimuli. Latency of inhibition of units in the dorsomedial hypothalamus was shorter than that of excitation. It is concluded that the hypothalamic non-nociceptive system is activated by innocuous stimuli and inhibited by nociceptive stimulation.