Mj. Runcie et al., EFFECTS OF PITUITARY ADENYLATE CYCLASE-ACTIVATING POLYPEPTIDE ON CARDIOVASCULAR AND RESPIRATORY RESPONSES IN ANESTHETIZED DOGS, Regulatory peptides, 60(2-3), 1995, pp. 193-200
This study examines some of the cardiovascular and respiratory effects
of pituitary adenylate cyclase-activating polypeptide (PACAP) in anae
sthetised dogs. Intravenous injection of PACAP 27 caused an increase i
n arterial blood pressure and an increase in heart rate. The blood pre
ssure response was significantly reduced by adrenoceptor blockade sugg
esting a mechanism of action mediated in part via catecholamines. The
heart rate increase was unaltered by adrenoceptor blockade suggesting
a direct effect of PACAP 27. PACAP 27 also caused potentiation of card
iac slowing caused by stimulation of the vagus nerve. In addition, PAC
AP 27 powerfully stimulated breathing. This was probably evoked by sti
mulation of arterial chemoreceptors, because bilateral section of the
carotid sinus nerves abolished this effect. PACAP 27 had no effect on
the ability of the cardiac sympathetic nerve to increase heart rate, n
or on the interaction between the sympathetic and parasympathetic syst
ems in the heart.