Effects of the CCK-A receptor antagonist CR 1409 on the activity of rat midbrain dopamine neurons.
Previous studies have shown that acute intravenous treatment with sulfated cholecystokinin octapeptide (CCK-8S) but not unsulfated CCK-8 increases the number of spontaneously active midbrain dopamine (DA) neurons. This suggested that a peripheral-type (CCK-A) CCK receptor mediates this effect. Proglumide does not discriminate between CCK-A and CCK-B (central-type) receptors. In the present study, rats were treated acutely or repeatedly (14 days) with the selective CCK-A antagonist CR 1409. Repeated treatment with 5 mg/kg (IP) increased the number of spontaneously active DA cells in the A10 (ventral tegmental area) but not the A9 (substantia nigra zona compacta) region, which suggests that these DA populations are differentially affected by prolonged CCK-A receptor blockade. The sensitivity of impulse-regulating DA autoreceptors to the DA agonist quinpirole was not altered by CR 1409.
Zhang
J
J
Laboratory of Neurophysiology, Sinai Research Institute, Detroit, MI 48235.
Chiodo
L A
LA
Freeman
A S
AS
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D004298:Dopamine / Q000502:physiology*; D004873:Ergolines / Q000494:pharmacology; D008297:Male; D008636:Mesencephalon / Q000187:drug effects* / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D011377:Proglumide / Q000031:analogs & derivatives* / Q000494:pharmacology; D019257:Quinpirole; D051381:Rats; D011919:Rats, Inbred Strains; D011949:Receptors, Cholecystokinin / Q000145:classification / Q000187:drug effects* / Q000502:physiology
D004873:Ergolines; D011949:Receptors, Cholecystokinin; D019257:Quinpirole; D011377:Proglumide; C048181:lorglumide; D004298:Dopamine