Distinct presynaptic control of dopamine release in striosomal and matrix areas of the cat caudate nucleus.
By use of a sensitive in vitro microsuperfusion method, the cholinergic prsynaptic control of dopamine release was investigated in a prominent striosome (areas poor in acetylcholinesterase activity) located within the core of cat caudate nucleus and also in adjacent matrix area. The spontaneous release of [3H]dopamine continuously synthesized from [3H]tyrosine in the matrix area was found to be twice that in the striosomal area; the spontaneous and potassium-evoked releases of [3H]dopamine were calcium-dependent in both compartments. With 10(-6) M tetrodotoxin, 5 x 10(-5) M acetylcholine stimulated [3H]dopamine release in both striosomal and matrix areas, effects completely antagonized by atropine (10(-6) M), thus showing the involvement of muscarinic receptors located on dopaminergic nerve terminals. Experiments without tetrodotoxin revealed a more complex regulation of dopamine release in the matrix: (i) In contrast to results seen in the striosome, acetylcholine induced only a transient stimulatory effect on matrix dopamine release. (ii) Although 10(-6) M atropine completely abolished the cholinergic stimulatory effect on [3H]dopamine release in striosomal area, delayed and prolonged stimulation of [3H]dopamine release was seen with atropine in the matrix. The latter effect was completely abolished by the nicotinic antagonist pempidine (10(-5) M). Therefore, in the matrix, in addition to its direct (tetrodotoxin-insensitive) facilitatory action on [3H]dopamine release, acetylcholine exerts two indirect (tetrodotoxin-sensitive) opposing effects: an inhibition and a stimulation of [3H]dopamine release mediated by muscarinic and nicotinic receptors, respectively.
Kemel
M L
ML
Laboratoire de Neuropharmacologie, Collège de France, Paris.
Desban
M
M
Glowinski
J
J
Gauchy
C
C
D000109:Acetylcholine / Q000494:pharmacology; D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002415:Cats; D002421:Caudate Nucleus / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D007700:Kinetics; D008297:Male; D008959:Models, Neurological; D010393:Pempidine / Q000494:pharmacology; D011976:Receptors, Muscarinic / Q000502:physiology; D011978:Receptors, Nicotinic / Q000502:physiology; D013569:Synapses / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology; D014443:Tyrosine / Q000378:metabolism
D011976:Receptors, Muscarinic; D011978:Receptors, Nicotinic; D014443:Tyrosine; D013779:Tetrodotoxin; D001285:Atropine; D000110:Acetylcholinesterase; D010393:Pempidine; D000109:Acetylcholine; D004298:Dopamine