[Electrophysiological and morphological characteristics of the visceral nociceptive neurons in cortex S II area of cats].

Electrophysiological and morphological properties of the visceral nociceptive neurons (VNNs) in the secondary somatosensory cortex (SII) area of 16 cats were investigated with intracellular recording and labeling method. Electrophysiological properties of a total of 251 neurons were identified, 109 of which were induced to discharge by stimulating the greater splanchnic nerve and therefore were simply designated as VNNs. Various patterns of the response could be recorded: excitatory (38.53%), inhibitory (42.20%) and excitato-inhibitory (19.31%). Following acquisition of electrophysiological data, neurobiotin was injected into 21 cells by electrophoresis to show their morphology and distribution in the cerebral cortex. It was found that excitatory VNNs were pyramidal neurons predominantly, whereas more inhibitory VNNs were stellate neurons.