Cholecystokinin-GABA interactions in rat striatum.
The release of [3H]gamma-aminobutyric acid ([3H]GABA) from rat striatal slices before and during electrical field stimulation (EFS) was measured. Electrical stimulation (10 Hz) induced an increase of Ca(++)- and tetrodotoxin-sensitive [3H]GABA release from the striatal slices. In the presence of sulphated octapeptide of cholecystokinin, CCK-8S (10(-9) M, 10(-8) M and 10(-7) M) both the basal and the electrically (10 Hz)-evoked release of [3H]GABA were dose-dependently increased. These effects of CCK-8S were abolished by tetrodotoxin (10(-6) M) and were not influenced by the CCK-A receptor antagonist loxiglumide (CR1505) (10(-7) M and 10(-6) M). The stimulant effect of CCK-8S was antagonized by the newly synthesized CCK-B selective receptor antagonist PD134308 (10(-7) M and 10(-6) M). These findings suggest that CCK-8 plays a neuromodulatory role in the regulation of GABAergic neuronal activity in the striatum. The activation of CCK-B receptors located on GABAergic neurons is involved in the GABA release-potentiating effect of CCK-8S in rat striatum.
Rakovska
A
A
Institute of Physiology, Bulgarian Academy of Sciences, Sofia, Bulgaria.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002766:Cholecystokinin / Q000037:antagonists & inhibitors; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004558:Electric Stimulation; D006727:Hormone Antagonists / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives / Q000494:pharmacology; D011377:Proglumide / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011949:Receptors, Cholecystokinin / Q000502:physiology; D012844:Sincalide / Q000031:analogs & derivatives* / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014316:Tritium; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
C090019:8-sulfocholecystokinin octapeptide; D006727:Hormone Antagonists; D007211:Indoles; D011949:Receptors, Cholecystokinin; D014316:Tritium; C065599:PD 134308; D013779:Tetrodotoxin; D005680:gamma-Aminobutyric Acid; D008536:Meglumine; C053737:loxiglumide; D002766:Cholecystokinin; D011377:Proglumide; D012844:Sincalide; D002118:Calcium