3.Ganglion-blocking agents. Not currently used clinically because of toxicity. Trimethaphan咪鏖吩：It competitively blocks nicotinic cholinergic receptors on postganglionic neurons,in both sympathetic and parasympathetic ganglia. The antihypertensive effect is due to pooling of blood in capacitance vessels. Antihypertensive effect is rapid,but excessive hypotension may occur. Adverse effects:(1)sympathoplegia(excessive orthostatic hypotension, sexual dysfunction);(2)parasympathoplegia(constipation,urinary retention, dry mouth,precipitation of glaucoma,etc.) 4.Agents that block adrenergic neurotransmitter synthesis and/or release. --Reserpine,guanethidine Reserpine Dopa 利血平 DD Reserpine Dopamine -0 DBH NE Mechanism of action:Interferes with the Mg2+and ATP-dependent uptake of biogenic amines,thereby depleting NE,dopamine,and serotonin.The effect is universal and irreversible.Reserpine acts both centrally and in the periphery.It decreases both CO and PVR. 1313 3. Ganglion-blocking agents. Not currently used clinically because of toxicity. Trimethaphan 咪噻吩: It competitively blocks nicotinic cholinergic receptors on postganglionic neurons, in both sympathetic and parasympathetic ganglia. The antihypertensive effect is due to pooling of blood in capacitance vessels. Antihypertensive effect is rapid, but excessive hypotension may occur. Adverse effects: (1) sympathoplegia (excessive orthostatic hypotension, sexual dysfunction); (2) parasympathoplegia (constipation, urinary retention, dry mouth, precipitation of glaucoma, etc.) 4. Agents that block adrenergic neurotransmitter synthesis and/or release. -- Reserpine, guanethidine Reserpine 利血平 Dopamine Dopa NE DBH ATP DD Reserpine Mechanism of action: Interferes with the Mg2+ and ATP-dependent uptake of biogenic amines, thereby depleting NE, dopamine, and serotonin. The effect is universal and irreversible. Reserpine acts both centrally and in the periphery. It decreases both CO and PVR