ABSTRACT
Previous research in our laboratory showed that stimulation of the vagina in rats with a probe inhibits withdrawal responses to noxious stimulation (Komisaruk and Larsson, 1971) and inhibits thalamic sensory neuronal response to noxious, but not innocuous, stimulation, providing evidence that vaginal stimulation induces analgesia (Komisaruk and Wallman, 1977). Subsequently, we reported that natural mating behavior in female rats produces analgesia during intromissions, and especially ejaculation, that is more potent than a supra-analgesic dose of morphine (Gomora, Beyer, Gonzalez-Mariscal, and Komisaruk, 1994).
