Peripheral postsynaptic alpha-adrenoceptor blocking properties of some new dihydrobenzofurane and imidazoline derivatives in pithed rats.
Peripheral postsynaptic alpha-adrenoceptor blocking properties of six new dihydrobenzofurane and imidazoline derivatives have been investigated in pithed rat against the pressor effects of phenylephrine and cirazoline (alpha 1-agonists) and clonidine and azepexole (alpha 2-agonists). Except for (N-methylimidazolinyl-2)-2 dihydro-2,3 benzofurane (II) that acted neither on alpha 1- nor alpha 2-adrenoceptors, all the compounds revealed blocking effects - plus or minor - on both alpha 1- and alpha 2-adrenoceptors. (Imidazolinyl-2)-2-chloro-7 dihydro-2,3-benzofurane (IV) is equipotent in blocking both alpha 1- and alpha 2-adrenoceptors. 7-Methoxy-(imidazolinyl-2)-2 dihydro-2,3-benzofurane (III) and (imidazolinyl-2)-2-fluoro-7-dihydro-2,3-benzofurane (V) block more effectively alpha 1- than alpha 2-adrenoceptors whereas (imidazolinyl-2)-2-benzocyclobutane (VI) is more potent in blocking alpha 2- than alpha 1-adrenoceptors. (Imidazolinyl-2)-2-dihydro-2,3-benzofurane (I) is a preferential alpha 2-adrenoceptor blocking agent. The most effective agents on alpha 2-adrenoceptors are under further pharmacological investigations.
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D001381:Azepines / Q000494:pharmacology; D001572:Benzofurans / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D003000:Clonidine / Q000494:pharmacology; D004347:Drug Interactions; D007093:Imidazoles / Q000494:pharmacology*; D008297:Male; D010627:Phenethylamines / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D017981:Receptors, Neurotransmitter / Q000187:drug effects*
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D001381:Azepines; D001572:Benzofurans; D007093:Imidazoles; D010627:Phenethylamines; D017981:Receptors, Neurotransmitter; D010656:Phenylephrine; C029261:phenethylamine; C015603:azepexole; D003000:Clonidine; C014282:cirazoline