VPT 321: Veterinary Neuropharmacology (2+1) copy 1

DIFFERENT NEUROTRANSMITTERS AND THEIR ROLE IN CNS

• Acetylcholine: Muscarinic M_{1 ­­}–M₅ subtypes and also nicotinic seen in CNS - Forebrain and striatum-inhibitory (muscarinic)
• Norpinephrine: α₁ and α₂ β₁ and β₂ -mainly in brain stem and reticular formation – control in sleep and wakefulness, mood and emotion, temperature etc.
• Epinephrine: seen in reticular formation. Role not well established.
• Dopamine: D₂  subtypes – in basal ganglia and limbic system. Behaviour disturbances, control of movements ( implicated in Parkinsonism) and in hypothalamic – pituitary system.
• 5-HT – multiple subtypes – sleep and wakefulness, mood and behaviour, appetite and neuroendocrine control.
• Aminoacids – Excitatory – Glutamate and Aspartate – 5 subtypes -- NMDA receptor – in dissociative anaesthesia, involved in epilepsy and anxiety states.
• GABA -Inhibitory -  major inhibitory.  Glycine – restricted to spinal cord and retina.
• Peptides – eg. Substance P – in pain perception, opioid peptides (endogenous opioids like endorphins and enkhepalins)– analgesia, behaviour and sedative actions.