Sensory requirements for the lordosis reflex in female rats

(1) Visual, auditory and olfactory input were not necessary for the performance of the lordosis reflex by female rats. Since taste is not involved in this behavior, somatosensory input must be sufficient for triggering the lordosis reflex. (2) Surgical cutaneous denervation markedly reduced the frequency and strength of lordosis. The most effective operation denervated the perineum, tailbase, posterior rump and ventral flanks. This pattern of results agrees with film observations and manual stimulation of lordosis. (3) Effects of surgical cutaneous denervation were confirmed in experiments with local anesthesia produced by subcutaneous procaine injections. (4) It is deduced that cutaneous mechanoreceptors in specific regions of hairy skin of the female rat play a crucial role in triggering the lordosis reflex.