RESPONSES OF NEURONS IN CAUDAL SOLITARY NUCLEUS OF FEMALE RATS TO STIMULATION OF VAGINA, CERVIX, UTERINE HORN AND COLON

Neurons in the caudal part of the solitary nucleus (NTS) are known for their processing of information derived from many viscera, including cardiovascular, respiratory and alimentary tract organs. This study ch aracterized responses of NTS neurons in female rats in estrus to mecha nical stimulation of four pelvic visceral organs (i.e.-the vaginal can al, cervix, uterine horn and colon) as well to gentle mechanical skin stimulation. Of the 90 neurons tested, 31% responded with excitation o r inhibition to one (22%) or more (9%) visceral stimuli. Responses inc luded 13% to vaginal distension, 12% to cervix stimulation, 10% to ute rine distension and 4% to colon distension. None responded to gentle c utaneous stimuli. These results expand the domain of visceral function s of NTS neurons to include pelvic female reproductive organs. The fai lure of NTS neurons to respond to gentle cutaneous stimuli contrasts w ith convergent responses of neurons in the gracile nucleus to skin and pelvic visceral stimuli [13] indicating the two nuclei are involved i n different aspects of visceral function.