Question

1. For each neurotransmitter listed below, indicate if the neurotransmitter is excitatory, inhibitory, or both when the neurotransmitter binds to its own receptor(s) (e.g. glycine binding to glycine receptor). Note: a response of both would mean that there are excitatory & inhibitory receptors for that neurotransmitter in different locations in the CNS and/or PNS.
   • ACh
   • NE & E
   • DA
   • 5-HT
   • Glutamate & Aspartate
   • GABA
   • Glycine

Answer 1

Ans- Ach - Both   Ach (Nicotinic) - Excitatory Ach (Muscarinic) - Inhibitory

* NE & E - Both excitatory and inhibitory

* DA - Generally excitatory; may be inhibitory at some sites, so both.

* 5- HT - Generally Inhibitory.

* Glutamate and Aspartate - Excitatory

* GABA - Inhibitory

* Glycine - Inhibitory

* Neurotransmitters released at an excitatory synapse causes a small depolarization in the postsynaptic membrane called an Excitatory postsynaptic potential (EPSP) , while neurotransmitter released at an inhibitory synapse generally causes a small hyperpolarization called inhibitory postsynaptic potential (IPSP).  

* EPSPs and IPSPs are produced by opening of Ligand gated channel, unlike action potentials , which are produced by opening of voltage gated channels.