PROCONFLICT EFFECT OF CARBON-DIOXIDE INHALATION IN RATS

The effect of brief inhalation of carbon dioxide (CO2) was studied in a conflict situation (Vogel test) in the rat. This treatment, which in hibits gamma-aminobutyric acid (GABA) mediated transmission in rat bra in and induces anxiety and panic attacks in humans, elicited a proconf lict effect. Exposure of rats for 1 min to CO2 decreased by similar to 40% the number of Licking periods in the test. This effect was abolis hed by prior administration of alprazolam (0.5 mg per kilogram of body mass, i.p.). Although these results may support a role for GABA-media ted transmission in the anxiogenic effect of CO2 inhalation, the possi bility that different neurotransmitters other than GABA are involved i n the action of CO2 can not be ruled out.