Responses of neurons in caudal solitary nucleus of female rats to stimulation of vagina, cervix, uterine horn and colon

Spinal and vagal influences on the responses of rat solitary nucleus neurons to stimulation of uterus, cervix and vagina

Neurons in the rat solitary nucleus (NTS) respond to mechanical stimulation of the uterine horn, cervix and vagina. The present study examined how these responses were affected by bilateral vagotomy and/or T10-T12 spinal transection for 12 single NTS neurons recorded in 12 rats anesthetized with halothane/nitrous oxide. Spinal transections all responses. Vagotomies eliminated responses only to uterine horn stimulation and either reduced the excitatory or enhanced the inhibitory responses to cervix and vaginal stimuli. These results suggest that NTS neuronal responses to cervix and vaginal stimulation depend upon input from the spinal dorsal horn and are facilitated by vagal input, whereas responses to uterine horn stimulation may require both spinal and vagal input.

Are there separate central nervous system pathways for touch and pain?

Information about bodily events is conveyed by primary sensory fibres to higher brain centres through neurons in the dorsal column nuclei (DCN) and spinal dorsal horn. The DCN route is commonly considered a 'touch pathway', separate from the spinal pain pathway', in part because DCN neurons respond to gentle tactile stimulation of small skin areas. Here we report that DCN neurons can additionally respond to gentle and noxious stimulation of viscera and widespread skin regions. These and other experimental and clinical data suggest that the DCN and spinal routes cooperate, rather than operate separately, to produce the many perceptions of touch and pain, an ensemble view that encourages novel approaches to health care and research.