Vol. 275, Issue 2, H717-H720, August 1998
RAPID COMMUNICATION
CNP causes receptor-mediated positive dromotropic effects in
anesthetized dog hearts
Masamichi
Hirose,
Yasuyuki
Furukawa,
Yusuke
Miyashita,
Fumio
Kurogouchi,
Koichi
Nakajima,
Masato
Tsuboi, and
Shigetoshi
Chiba
Department of Pharmacology, Shinshu University School of Medicine,
Matsumoto 390-8621, Japan
No data are
available for the direct effect of C-type natriuretic peptide (CNP) on
atrioventricular (AV) conduction in mammalian hearts. Thus we studied
the dromotropic effects of CNP-22 injected into the AV node artery in
autonomically decentralized hearts in open-chest, anesthetized dogs.
CNP decreased AV interval (AV conduction time) in a dose-dependent
manner with increase in coronary artery blood flow rate in six
anesthetized dogs. Isosorbide dinitrate did not affect AV interval, but
it increased coronary artery blood flow rate. A guanylyl cyclase-linked
natriuretic peptide receptor antagonist, HS-142-1, inhibited the
decreases in AV interval and the increases in coronary blood flow rate
in response to CNP, whereas propranolol did not affect the positive
dromotropic response to CNP. These results demonstrate that CNP
decreases AV interval and increases coronary artery blood flow rate
mediated by a guanylyl cyclase-linked natriuretic peptide receptor, but
not 
-adrenoceptor, in the dog heart.
C-type natriuretic peptide; atrioventricular conduction; HS-142-1
