Veterinary Neuropharmacology

GANGLIONIC BLOCKERS

• Small doses of nicotine can stimulate autonomic ganglion cells and large doses can block the transmitter functions of acetylcholine at the same sites.
• Though it was originally believed that ganglionic neurons have only nicotinic receptors, it has now been demonstrated that secondary excitatory pathway that is apparently muscarinic and inhibitory catecholaminergic mechanisms have also been demonstrated. But the drugs that exert significant autonomic ganglionic blocking effect do so, by blocking the nicotinic receptors.

Nicotine

• Nicotine is a liquid alkaloid obtained from the tobacco plant. (Nicotiana tobacum)
• Though it was the original autonomic ganglionic agent, it is not used clinically for this purpose.