[{"from": "human", "value": "Could you give me a brief overview of this molecule? [C][C][=C][C][=C][Branch1][Branch1][C][=C][Ring1][=Branch1][N][Branch1][=Branch2][C][C][=N][C][C][N][Ring1][Branch1][C][=C][C][=Branch1][=Branch1][=C][C][=C][Ring1][=Branch1][O]"}, {"from": "gpt", "value": "The molecule is a synthetic imidazoline with alpha-adrenergic antagonist activity. As a competitive alpha-adrenergic antagonist, phentolamine binds to alpha-1 and alpha-2 receptors, resulting in a decrease in peripheral vascular resistance and vasodilatation. This agent also may block 5-hydroxytryptamine (5-HT) receptors and stimulate release of histamine from mast cells."}]