One more question for pharmacologists and toxicologists?

Question

which heart rate changes could you see due to inhibition of nicotinic receptors by barbiturates ?

Answer 1

Nicotinic acid receptors are not influenced by barbiturates.

Answer 2

Barbiturates do indeed affect nicotinic receptors on autonomic ganglia. They also depress the vasomotor centers of the medulla, resulting in bradycardia (slower heart rhythm).

See the references below.