A comparison of peripheral pre- and postsynaptic alpha 2-adrenoreceptors using meta-substituted imidazolidines.
|
| Abstract |
1 The cardiac presynaptic activity, as derived from the inhibition of tachycardia to electrical stimulation of the cardiac sympathetic nerve in pithed, normotensive rats of 8 meta-substituted phenyl(imino)imidazolidines (2, 3- and 2,5- derivation) was determined. 2 The agonistic activity of the imidazolidines was measured with respect to vascular alpha 1- and alpha 2-adrenoreceptors. Accordingly, the increase in diastolic pressure of pithed, normotensive rats to intravenous administration of the imidazolidines was evaluated after pretreatment with 5% w/v glucose solution, yohimbine (1 mg/kg), prazosin (0.1 mg/kg) and the combination of both alpha-adrenoreceptor antagonists. 3 With respect to pre- and postsynaptic alpha 2-adrenoreceptors the 2,5-substituted derivatives were generally less active than the corresponding 2,3-substituted isomers. The steric bulk of the substituent at the 5-position of the imidazolidine molecule appeared to govern the activity with respect to cardiac presynaptic alpha 2-adrenoreceptors, whereas no such clear relationship could be derived for the activity on vascular postsynaptic alpha 2-adrenoreceptors. This indicates that there exists a close resemblance between pre- and post-synaptically located alpha 2-adrenoreceptors. However, these receptor sites are not identical.
|
|---|---|
| Authors | A De Jonge, P N Santing, P B Timmermans, P A Van Zwieten |
| Journal | Journal of autonomic pharmacology (J Auton Pharmacol) Vol. 1 Issue 5 Pg. 377-83 (Dec 1981) ISSN: 0144-1795 [Print] England |
| PMID | 6282886 (Publication Type: Comparative Study, Journal Article) |
| Chemical References |
|
| Topics |
|
Join CureHunter, for free Research Interface BASIC access!
Realize the full power of the drug-disease research graph!