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Actions of cocaine on rat dopaminergic neurones in vitro
Author(s) -
Lacey M.G.,
Mercuri N.B.,
North R.A.
Publication year - 1990
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1990.tb12998.x
Subject(s) - substantia nigra , dopamine , pars compacta , dopaminergic , ventral tegmental area , sulpiride , chemistry , membrane potential , neuroscience , electrophysiology , biophysics , pharmacology , biology
1 Intracellular recordings were made from neurones in vitro in the rat substantia nigra zona compacta and ventral tegmental area; the neurones had the characteristic properties of dopamine‐containing cells, and fired action potentials spontaneously. 2 Cocaine (1–10μ m ) inhibited spontaneous firing, hyperpolarized the membrane and (in neurones voltage‐clamped at −60 mV) caused an outward membrane current; the minimally effective concentration was 1 μ m . These effects were blocked by sulpiride (30 n m –1 μ m ). 3 Dopamine (3–100 μ m ) also inhibited firing, hyperpolarized and caused an outward current. These effects of dopamine were potentiated about five fold by cocaine (10 μ m ). 4 It is concluded that cocaine (1–10 μ m ) inhibits the firing and hyperpolarizes substantia nigra zona compacta neurones in vitro by blocking the uptake of dopamine which the cells continuously release.