Activation of GABA_A and GABA_B receptors in the lateral septum increases sucrose intake by differential stimulation of sucrose licking activity

摘要

The present study was aimed to determine how direct injections into the lateral septum (LS) of muscimol and baclofen, GABA_A and GABA_B receptor agonists, respectively, affect intake of 10% sucrose and sucrose licking activity in rats. The effects of muscimol and baclofen on the 1-h intake of sucrose and sucrose licking activity were tested at low (350pmol), medium (876pmol), and high (1752 pmol) doses. The medium and high doses of muscimol and the high dose of baclofen significantly increased 1-h sucrose intake. The total sucrose lick number was significantly increased by the medium dose of muscimol and the high dose of baclofen. An increase in sucrose licking activity induced by muscimol but not baclofen occurred in the first 15 min after injections. The medium and high doses of muscimol but not baclofen significantly decreased latency to initiate the first lick of sucrose. The total licking time calculated as the sum of the duration of all sucrose lick clusters showed a significant increase by the high dose of baclofen but not by any dose of muscimol.