Effects of acetylcholine on internal intercostal muscle activity in the rabbit.
In pentobarbitone-anesthetized rabbits, intracarotid injections of acetylcholine (ACh, 3-30 micrograms) during inspiration led to an inhibition of internal intercostal muscle activity (IIMA). After the section of the carotid sinus nerve (CSN), ACh-induced inhibitory responses in IIMA were abolished. In addition, changes of the rabbit carotid chemoreceptor activity were studied by ACh (3-30 micrograms) given into the carotid body region during inspiration. Spontaneous chemoreceptor activity was inhibited in a dose-dependent manner by ACh. These results suggest that the inhibitory responses of IIMA to ACh are probably mediated through the carotid chemoreceptor reflexes.
Matsumoto
S
S
First Department of Physiology, Fukushima Medical College, Japan.
Nagamine
T
T
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D002344:Carotid Body / Q000502:physiology; D002346:Carotid Sinus / Q000294:innervation / Q000502:physiology; D007366:Intercostal Muscles / Q000187:drug effects*; D009119:Muscle Contraction / Q000187:drug effects*; D011817:Rabbits
D000109:Acetylcholine