Neurotensin depolarizes substantia nigra dopamine neurones.

Neurotensin and the C-terminal 8-13 amino acid fragment were found to excite substantia nigra compacta dopamine neurones in vitro in a dose-dependent manner. The N-terminal 1-8 amino acid fragment was not active at the concentrations used. Desensitization was not observed. Intracellular recordings from the neurones responding to dopamine showed neurotensin-depolarized cells with an increase or no change in input resistance. These actions persisted in zero calcium, 8 mM magnesium artificial CSF suggesting a post-synaptic action.