EFFECT OF GLUCOSE AND 2-DEOXYGLUCOSE ON HYPOTHALAMIC GABA RELEASE IN LACTATING RATS

Gamma-amino butyric acid (GABA), an inhibitory neurotransmitter, has b een implicated in the control of feeding behavior. This study was cond ucted to investigate the in vitro release of GABA in the basal medial hypothalamus (BMH) of hyperphagic lactating (L) and control nonlactati ng (NL) rats. Pregnant Sprague-Dawley rats (n = 10) were ad lib fed a semipurified powdered diet during the last 6 days of pregnancy until d ay 19 of lactation. Nonpregnant (n = 10) animals served as controls. B ody weights and food intake were recorded every other day. Lactating r ats demonstrated an increase in body weight as well as food intake as compared to nonlactating animals. At sacrifice, the BMH was removed an d perfused (0.1 ml/min) with Kreb's Ringer buffer (KRB) (''basal'' med ium) using a Brandel perifusion system. KRB containing glucose (100 mM ) or 2-deoxyglucose (2DG) (100 mM) was also applied to the tissue. Pot assium stimulation was carried out to test for the viability of the ti ssues. Samples were collected every 10 min, derivatized with O-Phthala ldehyde and analyzed via HPLC. Glucose depressed, and 2DG enhanced GAB A release compared to basal levels. There were no significant differen ces in GABA release between lactating and nonlactating groups. These d ata suggest that GABA release is responsive to metabolic changes in th e brain. Copyright (C) 1997 Elsevier Science Inc.