A-77636 is a dopamine D1 receptor agonist (Ki = 40 nM). It induces activity equal to or greater than dopamine in an adenylate cyclase assay of D1 receptor activity in fish retina and rat caudate putamen (EC50s = 7.4 and 1.1 nM, respectively) but does not show agonist activity at D2 receptors expressed in MMQ cells when used at concentrations up to 10 μM. A-77636 (10 μM) induces desensitization of dopamine-stimulated cAMP accumulation and downregulation of D1 receptors, reducing D1 receptor expression by 79% in C-6 glioma cells expressing monkey D1A receptors. In a marmoset model of Parkinson''s disease induced by MPTP, A-77636 (3 μmol/kg, s.c.) increases locomotor activity 5.3-fold and reduces disease severity. Subcutaneous administration of A-77636 elicits cortical acetylcholine release at a dose of 1 μmol/kg. It also elicits over a 230% increase in cortical and hippocampal acetylcholine release when administered at a dose of 4 μmol/kg, an effect that is blocked by the D1 antagonist SCH 23390 .
The dopamine receptors play important role in cognition, memory, learning, and motor control (1). These receptors have been implicated as a therapeutic target for many psychiatric and neurological disorders. A 77636 Hydrochloride is a selective dopamine D1-like receptor agonist with antiparkinsonian properties (2,3).
ChEBI: (1R,3S)-3-(adamantan-1-yl)-1-(aminomethyl)-3,4-dihydroisochromene-5,6-diol hydrochloride is a hydrochloride salt obtained by mixing equimolar amounts of (1R,3S)-3-(adamantan-1-yl)-1-(aminomethyl)-3,4-dihydroisochromene-5,6-diol with hydrochloric acid. Potent and selective dopamine D1-like receptor agonist (pEC50 values are 8.97 and < 5 for D1-like and D2-like receptors respectively). Displays anti-Parkinsonian activity following oral administration in vivo. It has a role as an antiparkinson drug and a dopamine agonist. It contains a (1R,3S)-3-(adamantan-1-yl)-1-(ammoniomethyl)-3,4-dihydroisochromene-5,6-diol(1+).
Potent and selective dopamine D 1 -like receptor agonist (pEC 50 values are 8.97 and < 5 for D 1 -like and D 2 -like receptors respectively). Displays anti-Parkinsonian activity following oral administration in vivo .
[1]. kebabian jw, britton dr, deninno mp, et al. a-77636: a potent and selective dopamine d1 receptor agonist with antiparkinsonian activity in marmosets. eur j pharmacol, 1992, 229(2-3): 203-209.
[2]. lin cw, bianchi br, miller tr, et al. persistent activation of the dopamine d1 receptor contributes to prolonged receptor desensitization: studies with a-77636. j pharmacol exp ther, 1996, 276(3): 1022-1029.
[3]. acquas e, day jc, fibiger hc. the potent and selective dopamine d1 receptor agonist a-77636 increases cortical and hippocampal acetylcholine release in the rat. eur j pharmacol, 1994, 260(1): 85-87.
