The interaction of chlordimeform, N'-demethylchlordimeform [N2-(4-chloro-o-toly1)-N'-methylformamidine], BTS-27271 (N'-methyl-N2-(2,4-xylyl)formamidine, the 2,4-xylyl analogue of N'-demethylformamidine], and amitraz with octopamine-, dopamine-, and 5-hydroxytryptamine-mediated enhancement of cyclic-AMP production was investigated in nerve cord homogenates of the American cockroach Peripfunetu umericuna. N'-Demethylchlordimeform, BTS-27271 and amitraz simulated the actions of the monoamines in enhancing cyclic-AMP production, whereas chlordimeform showed no such agonism. Additivity studies indicated that these formamidine derivatives were interacting with dopamine-and 5hydroxytryptamine-sensitive sites, in addition to their known interaction with octopamine-sensitive adenylate cyclase. N'-Demethylchlordimeform (Ki= 0 . 2~~) and amitraz ( K i = 0 . 5 p~) inhibited the dopamine-mediated response, but only N'-demethylchlordimeform ( K i = 2 p~) effected appreciable inhibition of the octopamine-response. Pharmacological characterisation of the formamidineinduced elevation of cyclic-AMP production indicated that the agonistic effects of formamidines are expressed primarily through the octopamine-sensitive adenylate cyclase, rather than the dopamine-or 5-hydroxytryptamine-sensitive sites. The results are discussed in the light of the proposal that the behavioural changes, associated with formamidine poisoning, reflect the cumulative effects of octopamine-agonism, and antagonism of the dopamine-and 5-hydroxytryptaminemediated processes.
During pseudopregnancy in the rabbit, plasma progesterone levels in the posterior vena cava fell rapidly from maximal concentrations of 9.8 +/- 0.7 (s.e.m.) ng/ml on Day 13 of pseudopregnancy to 2.0 +/- 0.6 ng/ml on Day 15. There was no significant increase in PGF levels at this time, although administration of indomethacin to a similar group of does delayed functional regression for over 7 days. Subcutaneous injection of 1 mg PGF-2alpha or 35 mg arachidonic acid on Day 9 of pseudopregnancy resulted in loss of luteal function as plasma progesterone levels fell significantly from about 6 to less than 1 ng/ml within 24 h. These findings indicate that the uterine factor responsible for luteolysis in the pseudopregnant rabbit may not be released in the form of PGF-2alpha.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations –citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.