A change in the spontaneous release of endogenous acetylcholine from rat striatal slices after repeated injection of haloperidol.
The spontaneous and 50 mM K(+)-stimulated release of endogenous acetylcholine (ACh) from rat striatal slices was measured to investigate an adaptive change of striatal ACh after a withdrawal period for 24 h from chronic treatment of the rat with haloperidol. The haloperidol injections (2.5 mg/kg/day) for a period of 3, 7 or 14 days all reduced the spontaneous release of ACh significantly by 20-50% without changing tissue levels of ACh. On the contrary, these treatments produced a very small (by about 10%) but significant increase in K(+)-stimulated release except for the treatment of 7 days. These results suggest that the spontaneous ACh release is under the control of a dopaminergic mechanism, which might be different from the mechanism controlling the evoked release of ACh and emerges following withdrawal from chronic haloperidol treatment.
Umeda
Y
Y
Division of Psychopharmacology, Psychiatric Research Institute of Tokyo, Japan.
Watanabe
C
C
Sumi
T
T
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects / Q000502:physiology*; D006220:Haloperidol / Q000494:pharmacology*; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values
D006220:Haloperidol; D000109:Acetylcholine; D011188:Potassium