The effect of microinjections of the 5-HT2A/2C receptor antagonist RP62203 (1,0; 2,5; 5,0 mg) in the amygdala was investigated on traditional and ethological (scanning, risk-assessment, explorations of extremities) anxiety measures of rats in the elevated plus-maze test. The dose of 5,0 mg increased the percentages of entries and time spent in the open arms, without altering the number of closed arm entries. Scanning, risk-assessment and end exploration were also changed by the treatment, there being an increase of time spent in scanning (2,5 and 5,0 mg) and a reduction of time in risk-assessment (2,5 and 5,0 mg). The number of explorations of extremities was increased by the dose of 5,0 mg. This behavioral profile suggests an anxiolytic effect of the RP 62203. The participation of the 5-HT2A/2C receptors of the amygdala in the regulation of those effects is discussed.
anxiety; elevated plus-maze; 5-HT
