Role of muscarinic acetylcholine receptors in a guinea pig model of asthma.
We examined the density of muscarinic acetylcholine receptor (mACh-R) subtypes (M1R, M2R and M3R) in guinea pig lung. The density of M3R in the lung tissue of ovalbumin (OA)-sensitized guinea pigs was higher than that in the control group. However, no difference was observed in the affinity of M3R between the sensitized and the control lungs. No difference was observed in the density and affinity of M1R and M2R in sensitized and control lungs. Pilocarpine, which is an M2R stimulant, increased the density of M3R in the lung tissue and the rate of the increase in sensitized guinea pigs was less than that in the control group. In contrast, methoctranine, which is an M2R antagonist, decreased the density of M3R and the rate ofthis decrease was the same in the sensitized and control groups. These results suggest that, in OA-sensitized guinea pigs, a dysfunction of M2R leads to the abnormal density of M3R.
Tohda
Yuji
Y
Fourth Department of Internal Medicine, Kinki University School of Medicine, Osakasayama, Osaka, Japan. access-planning@eva.hi-ho.ne
Haraguchi
Ryuta
R
Itoh
Mari
M
Ohkawa
Kentaroh
K
Kubo
Hirokazu
H
Fukuoka
Masahiro
M
Nakajima
Shigenori
S
D000818:Animals; D001249:Asthma / Q000503:physiopathology*; D003959:Diamines / Q000494:pharmacology; D005703:Gallamine Triethiodide / Q000494:pharmacology; D006168:Guinea Pigs; D008566:Membranes / Q000187:drug effects / Q000378:metabolism; D018721:Muscarinic Agonists / Q000494:pharmacology; D018733:Nicotinic Antagonists / Q000494:pharmacology; D010047:Ovalbumin / Q000276:immunology; D010276:Parasympatholytics / Q000494:pharmacology; D010862:Pilocarpine / Q000494:pharmacology; D043585:Receptor, Muscarinic M2; D043587:Receptor, Muscarinic M3; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000502:physiology*
D003959:Diamines; D018721:Muscarinic Agonists; D018733:Nicotinic Antagonists; D010276:Parasympatholytics; D043585:Receptor, Muscarinic M2; D043587:Receptor, Muscarinic M3; D011976:Receptors, Muscarinic; D010862:Pilocarpine; D010047:Ovalbumin; C054938:methoctramine; D005703:Gallamine Triethiodide