Without the voltage channels of the axons, the membrane potential changes induced by the neurotransmitters at the synapse are not all or none. At the neuromuscular junctions , the postsynaptic membrane is the motor end plate . EPSPs lead to opening of voltage-regulated gates, which lead to action potentials in muscle fibers. The ACh-receptor interaction is brief, but can quickly return as long as there's free ACh around. In the CNS, many monamines can act as neurotransmitters.
Dopamine is used as a neurotransmitter in dopaminergic neurons.
These neurons are concentrated in the substantia nigra of the midbrain, sending fibers to the basal nuclei. Dopamine blockade in the mesolimbic system is beneficial for schizophrenia , but blockade at other regions is not, e.g., blockade of the dopamine receptors in the pituitary lead to interference with PIH function, so high prolactin levels. 2 Serotonin is found in serotonergic neurons innervating many parts of the CNS, with their cell bodies found in the brain stem. GABA is the most prevalent neurotransmitter in the brain. It is inhibitory and involved in motor control, e.g., large Purkinje cells of cerebellum.