A 77636 hydrochloride

A 77636 hydrochloride is a potent and selective agonist of dopamine D1 receptor with Ki value of 39.8 nM [1].

Dopamine D1 receptor is a G-protein couple receptor for dopamine and stimulates adenylate cyclase and cyclic AMP-dependent protein kinases. Dopamine D1 receptor plays an important role in behavioral responses and neuronal growth and development.

A 77636 hydrochloride is a potent and selective dopamine D1 receptor agonist. A-77636 exhibited agonist activities with pEC50 values of 8.13 and 8.97 in the fish retina and the rat caudate-putamen, respectively [1]. In SK-N-MC neuroblastoma cell line, A-77636 significantly induced residual cAMP production [2].

In rats and mice, A-77636 induced forelimb clonus. In marmosets, A-77636 increased locomotor activity and inhibited the parkinsonian-like symptoms induced by MPTP [1]. In rat, A-77636 (4 μmol/kg) significantly increased acetylcholine release in both cortical and hippocampal. However, at a lower dose (1 μmol/kg) A-77636 only stimulated cortical acetylcholine release [3].

References:
[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.