Low threshold mechanical stimulation of the vagina depresses dorsal horn unit activity in the spinal cat.
Low threshold (0.5-15 g) mechanical punctate stimulation of the labia and vagina depressed dorsal horn neurones in the cat with spinal transection at L1. Similar stimulation 2 mm or more from the outer margin of the labia was without effect. The depression was observable within 1-2 sec, and usually required 4-6 min for full recovery, although a smaller more prolonged depression may also have occurred. Stronger stimuli evoked greater inhibition, requiring longer times for recovery. Vaginal stimulation depressed 9 of 10 sensory dorsal horn neurones (including non-nociceptive, wide dynamic range and nociceptive specific). Depression included a decrease in spontaneous activity and a decrease of naturally elicited responses to noxious and innocuous cutaneous stimuli; therefore the effect is not modality related. One unit without sensory input was unaffected by vaginal stimulation. In the one case tested, vaginal stimulation depressed glutamate-evoked excitation, suggesting that the depression of naturally, elicited responses was via a postsynaptic mechanism.
D000818:Animals; D002415:Cats; D003655:Decerebrate State; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D005836:Genitalia, Female / Q000502:physiology; D005971:Glutamates; D018698:Glutamic Acid; D008465:Mechanoreceptors / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology*; D009619:Nociceptors / Q000502:physiology*; D010812:Physical Stimulation / Q000379:methods; D012684:Sensory Thresholds; D013116:Spinal Cord / Q000502:physiology*; D013268:Stimulation, Chemical; D014621:Vagina / Q000502:physiology*; D014844:Vulva / Q000502:physiology
D005971:Glutamates; D018698:Glutamic Acid