Behavior of High- and Low-Anxiety Rats on the Background of Modulation of GABAergic Transmission in the Basolateral Nucleus of the Amygdala

Abstract

The effects of local administration into the right or left basolateral amygdalar nucleus of a GABAA receptor agonist (muscimol hydrobromide, 0.1 μg/0.5 μl) or antagonist (bicuculline methiodide, 0.2 μg/0.5 μl) on behavior in the elevated plus maze were studied in high- and low-anxiety rats. High- and low-anxiety rats had different sensitivities to these substances. Administration of muscimol had anxiolytic actions only in high-anxiety rats, increasing the duration of excursions into the open arms of the maze. Administration of bicuculline led signs of aggressivity in all rats, with increases in motor and exploratory activity in high-anxiety rats and increases in the duration of excursions into the open arms of the maze and emotional tension in low-anxiety animals. More effective changes in behavior were seen with administration of muscimol into the left amygdala of high-anxiety rats and with bicuculline into the right amygdala of low-anxiety rats. These results provide evidence of the existence of individual-typological and interhemisphere differences in the functioning of the GABAergic system of the amygdala.