Peripheral airway hyperresponsiveness in the choline-deficiently fed rat.
Rats fed with choline-deficient diets are known as a model of aging and learning impairments due to acetylcholine (ACh) deficiency in the brain which may be associated with a decrease in acetylcholinesterase (AChE; EC 3.1.1.7). To determine the role of AChE in bronchial responsiveness, we examined the contractile response of isolated lung parenchymal strips to ACh in control rats and rats fed with choline-deficient diets. Concentration-response curves to ACh shifted to the lower concentrations and the maximum response to ACh was greater in rats fed with choline-deficient diets than in control rats (P < 0.01). Physostigmine (10(-6) M) mimicked effects of choline-deficient diets on the contractile response to ACh. However, concentration response curves to carbachol and 5-hydroxytryptamine did not differ between control rats and rats fed with choline-deficient diets. Choline-deficient diets significantly decreased the AChE activity from homogenates of lung parenchymal tissues (P < 0.01). These results suggest that a decrease in AChE activity of lung tissues may relate to airway hyperresponsiveness to ACh.
Itabashi
S
S
Department of Geriatric Medicine, Tohoku University School of Medicine, Sendai, Japan.
Ohrui
T
T
Sekizawa
K
K
Matsuzaki
Y
Y
Sasaki
H
H
D000109:Acetylcholine / Q000494:pharmacology; D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D016535:Bronchial Hyperreactivity / Q000201:enzymology*; D002217:Carbachol / Q000494:pharmacology; D002796:Choline Deficiency / Q000201:enzymology*; D004032:Diet; D008168:Lung / Q000201:enzymology; D008297:Male; D009119:Muscle Contraction; D051381:Rats; D017208:Rats, Wistar
D002217:Carbachol; D000110:Acetylcholinesterase; D000109:Acetylcholine