VESICO-SYMPATHETIC REFLEXES IN CAT VASOCONSTRICTOR NEURONS SUPPLYING SKIN AND SKELETAL-MUSCLE DEPEND ON THE INTEGRITY OF THE SACRAL BLADDERAFFERENTS

In anesthetized cats, distension of the urinary bladder induces powerf ul reflexes in postganglionic sympathetic neurones projecting to the h indlimb: muscle vasoconstrictor neurones (MVC) are excited and cutaneo us vasoconstrictor neurones (CVC) are inhibited. We investigated these reflexes quantitatively before and after sacral rhizotomy. The reflex responses in MVC and CVC neurones were completely abolished after eli mination of the pelvic afferent input demonstrating that these reflexe s are generated exclusively by excitation of sacral bladder afferents. The activation of lumbar bladder afferents which are supposed to be a ble to elicit painful sensations did not contribute to vesico-sympathe tic reflexes in MVC and CVC neurones.