Effect of caerulein (CLN) and CCK-8 on the GABA levels and GABA turnover in discrete brain regions in mice

• Published in: Japanese Journal of Pharmacology 1989, Vol.49 (suppl), p.311-311
• Main Authors: Nagahama, Hiromichi, Murai, Shigeo, Miyate, Hiroki, Saito, Hiroko, Masuda, Yoshikatsu, Itoh, Tadanobu
• Format: Article
• Language: English
• ISSN: 0021-5198; 1347-3506
• DOI: 10.1016/S0021-5198(19)56770-1

CLN and CCK-8 antagonize drug induced convulsion in mice, suggesting that these peptides may have some effects on the central GABAergic system. Thus, we have studied the effects of CLN (0.5, 5, 50 μg/kg, i.p.) and CCK-8 (5, 50, 400 μg/kg, i.p.) on the GABA levels and GABA turnover in discrete brain regions of mice. GABA turnover was measured by pretreatment with aminooxyacetic acid. Mice were killed by microwave irradiation 30, 60 and 120 min after the drugs were given. The corpus striatum (ST), hypothalamus (HT), frontal cortex (FC) and nucleus accumbens (NA) were isolated from the brain, and perchloric acid extracts of these tissues were mixed with o-phthalaldehyde/B-mercaptoethanol solution and injected onto the HPLC-ECD system. The effects of CLN and CCK 8 on the GABA levels were similar to each other：both peptides decreased the GABA levels in the ST and NA, whereas they increased in the HT and FC. CLN decreased GABA turnover in the ST and HT. These results suggest a possibility that peripheral administration of CLN and CCK 8 has a complex influence on the central GABAergic system, depending on the brain regions and dosage.