"On-line" measurement of acetylcholinesterase release from the substantia nigra of the freely-moving guinea-pig.
Acetylcholinesterase is released from dopaminergic cells within the substantia nigra. The functional significance of this phenomenon has been studied in the freely-moving animal by a novel system for measuring acetylcholinesterase release from the substantia nigra "on-line" and in vivo. In the unanaesthetized guinea-pig the amount of acetylcholinesterase released was significantly greater than during anaesthesia, and release occurred in a more pulsatile manner. In addition, release of acetylcholinesterase could be evoked by either pharmacological or physiological manipulations, i.e. (1) a depolarizing concentration of potassium ions administered locally; (2) metamphetamine, administered systematically, which also resulted in increased locomotor activity; (3) drinking behaviour, elicited by presentation of a water bottle. Although all three treatments were accompanied by an increase in acetylcholinesterase release within the substantia nigra, potassium-evoked release did not cause any detectable change in behaviour. It is therefore suggested that release of the protein acetylcholinesterase within the substantia nigra is not necessarily a direct cause of locomotor activity: rather, it reflects diverse sensorimotor events.
Taylor
S J
SJ
University Department of Pharmacology, Oxford, U.K.
Jones
S A
SA
Haggblad
J
J
Greenfield
S A
SA
D000110:Acetylcholinesterase / Q000378:metabolism*; D000758:Anesthesia; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002093:Benzenaminium, 4,4'-(3-oxo-1,5-pentanediyl)bis(N,N-dimethyl-N-2-propenyl-), Dibromide / Q000494:pharmacology; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D004327:Drinking Behavior / Q000187:drug effects; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology; D009043:Motor Activity / Q000502:physiology; D010477:Perfusion; D011188:Potassium / Q000494:pharmacology; D013239:Stereotyped Behavior / Q000502:physiology; D013378:Substantia Nigra / Q000033:anatomy & histology / Q000378:metabolism*
D002800:Cholinesterase Inhibitors; D002093:Benzenaminium, 4,4'-(3-oxo-1,5-pentanediyl)bis(N,N-dimethyl-N-2-propenyl-), Dibromide; D008694:Methamphetamine; D000110:Acetylcholinesterase; D011188:Potassium