A drug selectively blocks nicotinic receptors within ganglia

A drug selectively blocks nicotinic receptors within ganglia of the autonomic nervous system. This drug will

A: only block sympathetic activity on the heart

B: block neither parasympathetic nor sympathetic activity on the heart.

C: only block parasympathetic activity on the heart

D: block both parasympathetic and sympathetic activity on the heart

Solution

Answer D: Block both parasympathetic and sympathetic activity on the heart.

Nicotinic receptors mainly transmit signals from the pre-synaptic to the postsynaptic cells (outgoing signals) within the sympathetic and parasympathetic nervous system. Nicotinic receptors are found on skeletal muscles and acetylcholine acts on these receptors to signal muscle contraction.

So blocking nicotinic receptors blocks both parasympathetic and sympathetic activity of the heart.