Respiratory response to spontaneous contractions of the urinary bladder inawake and decerebrate rats

Spontaneous contractions of the urinary bladder (SBCs) have been shown to d ecrease the frequency and depth of respiration in anesthetized or unanesthe tized, decerebrate cats. The respiratory responses to bladder voiding refle xes in the awake state have not been previously addressed. Because a chroni c rat model for the study of bladder function has been established and brea thing measurements can be made in the awake rat, we chose the rat as an exp erimental model to assess whether SBCs would alter breathing in the conscio us, intact animal. Respiratory frequency increased during bladder contracti ons but tidal volume remained unaffected. To assess whether the respiratory response to bladder reflexes in rats differed from that previously observe d in cats, we also studied decerebrate, vagotomized, paralyzed and artifici ally ventilated rats. Contrary to the respiratory inhibition observed in de cerebrate cats, phrenic and hypoglossal nerve activities remained unaffecte d during SBCs in decerebrate rats. These results indicate a species differe nce in the coupling between respiration and bladder voiding reflexes. (C) 2 000 Elsevier Science B.V. All rights reserved.