... (nicotinic receptors, Naf), ATP (P2X receptors, Naf), glutamate (Glu) (non-N-methyl-1,-aspartate (NMDA) receptors, Naf), glutamate (NMDA receptors, Na+ and Ca2+), serotonin (HT3 receptors, Na+ ... serotonin) receptors (5HT3-Rs) are excitatory 5HT-gated, perltameric cation channel receptors that become selectively permeable to Na+ and Ca"+ on binding 5HT with consequent excitatory ... respect to the outside) (Table 3.3). 90 3. Neurotransmitter- and hormone-gated ion channels Inhibitory glutamate receptors (iGlu-Rs) are inhibitory, Glu-gated ion channels related to the...