The affinity of some acetylenic analogues of 4-DAMP methobromide for muscarinic receptors in guinea-pig ileum and atria.
1. The replacement of 4-hydroxy-N-methyl piperidine (HO NMe) in 4-diphenylacetoxy-N-methyl piperidine (4-DAMP) metho-bromide by 4-hydroxy-but-2-ynylamines (HOCH2C=CCH2NR2) reduces the affinity for muscarine-sensitive acetylcholine receptors in guinea-pig ileum and atria. It does not abolish selectivity. The tertiary amines are more active and more selective than the corresponding quaternary salts. 2. Analogous derivatives of 4-hydroxy-but-2-ynylamines which lack the ester group (i.e. substituted 4-hydroxymethyl-propynyl amines) are less active and less selective. The quaternary compounds are more active than the tertiary bases. 3. The diphenylcarbamyl ester of 4-hydroxy-N-methylpiperidine methobromide has less than one-thousandth of the activity of the diphenylacetyl ester (4-DAMP methobromide) and is not selective. 4. Although 4-diphenylacetoxy-butynyl dimethylamine is only about one-hundredth as active as 4-DAMP methobromide it appears to have comparable selectivity. It is an interesting compound because it is a tertiary amine and should cross membranes.
Barlow
R B
RB
Department of Pharmacology, Medical School, Bristol.
Shepherd
M K
MK
Tydeman
H
H
Veale
M A
MA
D000818:Animals; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D010880:Piperidines / Q000494:pharmacology*; D011976:Receptors, Muscarinic / Q000187:drug effects*; D013329:Structure-Activity Relationship
D010880:Piperidines; D011976:Receptors, Muscarinic; C042375:4-diphenylacetoxy-1,1-dimethylpiperidinium