Effect of ageing on response to nicotine in rabbit bronchial preparation.
1. Effect of ageing on the response to nicotine was tested in the bronchial muscle preparations from 5, 13, 100 and 125 week-old rabbits. The pD2 value (potency) of nicotine significantly increased in the preparation from the 125 week-old rabbits. No age-related change was found in the pD2 value of carbamylcholine or pA2 value of atropine. 2. No age-related change in characteristics of nicotine receptors. Choline acetyltransferase activity, the amount of acetylcholine released by nicotine and acetylcholineesterase activity decreased in the preparations from the 125 week-old rabbits. 3. Decrease in the pD2 value of nicotine in the preparation from the older rabbit is due to a decline in choline acetyltransferase activity followed by a reduction in the acetylcholine released, and not to a change in characteristics of nicotine receptors. 4. These results also suggest that enzymes may be influenced more easily with age than drug receptors.
Takayanagi
I
I
Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, Chiba, Japan.
Moriya
M
M
Kizawa
Y
Y
Koike
K
K
Shinkai
M
M
Murakami
H
H
D000109:Acetylcholine / Q000378:metabolism / Q000494:pharmacology; D000110:Acetylcholinesterase / Q000378:metabolism; D000375:Aging / Q000502:physiology*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001980:Bronchi / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D002217:Carbachol / Q000494:pharmacology; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D005260:Female; D006584:Hexamethonium Compounds / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008566:Membranes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D009538:Nicotine / Q000494:pharmacology*; D011817:Rabbits; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000378:metabolism
D006584:Hexamethonium Compounds; D011978:Receptors, Nicotinic; D009538:Nicotine; D001285:Atropine; D002217:Carbachol; D002795:Choline O-Acetyltransferase; D000110:Acetylcholinesterase; D000109:Acetylcholine