Guanethidine lowers blood pressure by which mechanism?

Guanethidine lowers blood pressure by which mechanism?

• A. Blocking NE release from nerve terminals
• B. Entering sympathetic neurons and displacing NE from storage vesicles
• C. Inhibiting NE synthesis
• D. Blocking alpha receptors

Answer: (B)

Guanethidine acts as a false transmitter in sympathetic nerves. It is taken up into sympathetic terminals by the norepinephrine transporter and accumulates in storage vesicles, where it displaces stored norepinephrine. This depletion of NE in the terminals means less NE is released during nerve stimulation, reducing vasoconstrictor input to blood vessels and lowering blood pressure. It does not block alpha receptors or inhibit NE synthesis, and its primary effect is depletion of NE stores via uptake into the neuron and displacement from vesicles.

Guanethidine acts as a false transmitter in sympathetic nerves. It is taken up into sympathetic terminals by the norepinephrine transporter and accumulates in storage vesicles, where it displaces stored norepinephrine. This depletion of NE in the terminals means less NE is released during nerve stimulation, reducing vasoconstrictor input to blood vessels and lowering blood pressure. It does not block alpha receptors or inhibit NE synthesis, and its primary effect is depletion of NE stores via uptake into the neuron and displacement from vesicles.