PT  - JOURNAL ARTICLE
AU  - I Creese
AU  - S H Snyder
TI  - Receptor binding and pharmacological activity of opiates in the guinea-pig intestine.
DP  - 1975 Jul 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 205--219
VI  - 194
IP  - 1
4099  - http://jpet.aspetjournals.org/content/194/1/205.short
4100  - http://jpet.aspetjournals.org/content/194/1/205.full
SO  - J Pharmacol Exp Ther1975 Jul 01; 194
AB  - A comparison was made between the affinities of a wide range of opiate agonists, mixed agonist-antagonists and antagonists for opiate receptor binding sites in the guniea-pig intestine longitudinal muscle and myenteric plexus preparation, and their pharmacological potency in influencing the electrically induced contraction of this in vitro functional system. The relative affinities of drugs and the degree of stereospecificity for intestinal binding sites are closely similar to these properties in the brain. Receptor binding correlates extremely well with pharmacological potency, both for agonists and antagonists, indicating that binding involves pharmacologically relevant opiate receptors. Pharmacological activity correlates best with receptor binding assayed in the presence of sodium.