Lack of effects of handling habituation and swimming stress on ethanol-induced motor impairment and GABAA receptor function.

The effects of handling habituation and swimming stress on ethanol-induced motor impairment and the GABAA receptor function were studied in adult male Wistar rats. Daily handling for 3 to 5 weeks had no significant effect on ethanol-induced motor impairment in the tilting plane test or on the activity of the rats in the elevated plus-maze test of anxiety. Plasma corticosterone concentrations were greatly elevated by the tilting plane test procedure, irrespective of handling habituation. Acute, 10-min swimming stress at +25 degrees C produced an elevated plasma corticosterone concentration comparable to that produced by the tilting plane test, again irrespective of handling habituation. In cerebrocortical homogenates, short-term swimming stress had no statistically significant effect on the muscimol stimulation of the GABAA receptor-mediated 36Cl- flux in handled and non-handled animals. Thus, handling habituation and stress had only minor effects on the activity of the central GABAergic systems in acute tests at behavioural and biochemical levels.