Veterinary Neuropharmacology

EFFERENT FIBRES

• In efferent fibres two neurons (Preganglionic and Post ganglionic fibres) + effector cells / target organs are generally involved.
• Preganglionic fibres
  • Exit the spinal cord and terminate in ganglia
  • Acetylcholine (ACh) is the neurotransmitter released by the preganglionic nerves in autonomic ganglia. This connection is known as nicotinic cholinergic synapse.
• Postganglionic fibres
  • Exit from ganglia and innervate the effector cells /organs
  • Neurotansmitters released at the neuroeffector junctions depending on the innervation 
    • ACh mediates muscarinic cholinergic transmission
    • Norepinephrine mediates adrenergic transmission
  • Adrenal medulla is an exception embryologically where ganglionic transmission causes release of epinephrine ( adrenaline) into the blood