Dopamine Control of Excitability Changes in Nigrostriatal Terminals
The role of autoreceptors in the control of metabolism and release of dopamine at the level of the axonal terminal has been studied from a pharmacological and biochemical point of view. Recently the electrical results of autoreceptor activation at the terminal level have been studied by measuring the excitability of the terminals while recording the evoked antidromic activity at the level of the soma. Electrical stimulation of the frontal cortex decreases the excitability of the dopamine containing terminals in the striatum of the rat. In this experiment the involvement of dopamine in the decrease in excitability observed after frontal cortex stimulation was investigated. Depletion of dopamine by pretreatment with alpha-methylparatyrosine (AMPT), or AMPT plus reserpine, prevents the observed changes in excitability. These results suggest that the effects of cortical stimulation are mediated indirectly through the release of endogenous dopamine and activation of autoreceptors.
KeywordsCortical Stimulation Nigrostriatal Pathway Excitability Change Terminal Field Endogenous Dopamine
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