Veterinary Neuropharmacology

CO - TRANSMISSION

• It was believed that there is One neuron – One transmitter model which  is an oversimplification.
• Many peripheral and central neurons have been shown to release more than one active substance when stimulated.
• Cholinergic and adrenergic neurons elaborate ATP, Purines, Peptides, VIP, Neuropeptide Y, Substance P, Enkephalins and prostaglandins as co - transmitters.
• Co - transmitter is not stored in the same neuron, but in distinct synaptic vesicles or locations.
• On being released by the nerve impulse, it may serve to regulate the presynaptic release of the primary transmitter and/or post synaptic sensitivity to it.