Reflex adrenal medullary secretion during coronary occlusion mediated by cardiac receptors with afferent vagal fibres in the rat.
The relative contribution of ventricular receptors and sinoaortic baroreceptors to the reflex release of adrenaline upon coronary occlusion was studied in anaesthetised rats submitted to a 30-min occlusion of the left coronary artery. Arterial adrenaline concentrations, heart rate and blood pressure were evaluated in control and sham-operated rats, and following sinoaortic denervation (SAD), bilateral vagotomy with and without SAD, ventricular application of lidocaine, neonatal treatment with capsaicin and cervical section of teh spinal cord. In all groups submitted to coronary ligation, blood pressure decreased sharply upon ligation and remained significantly reduced throughout occlusion while heart rate changes were not significant. In control rats, arterial adrenaline concentrations were significantly increased 15 and 30 minutes following coronary occlusion. The increase in adrenaline concentrations observed upon coronary ligation following SAD was not different from that of the control group. On the other hand, vagotomy with or without SAD, ventricular application of lidocaine, neonatal capsaicin treatment and spinal section all greatly reduced the increase in plasma adrenaline values. These results suggest that a large part of the reflex release of adrenaline upon coronary occlusion is mediated by ventricular receptors with unmyelinated vagal afferent fibres.
Godin-Ribuot
D
D
Laboratoire de physiologie et pharmacologie - PCEBM, Faculté de Pharmacie, Université Grenoble I, F-38706 La Tronche Cedex, France.
Ribuot
C
C
Lamontagne
D
D
Yamaguchi
N
N
Couture
R
R
de Champlain
J
J
Demenge
P
P
Nadeau
R
R
D000313:Adrenal Medulla / Q000378:metabolism*; D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D003327:Coronary Disease / Q000503:physiopathology*; D006321:Heart / Q000502:physiology*; D008297:Male; D011311:Pressoreceptors / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012018:Reflex / Q000502:physiology*; D014630:Vagus Nerve / Q000502:physiology*