[Effect of hypobaric hypoxia on motor behavior in rats]

Hypobaric hypoxic exposure for 18 h (pO2 8.7 kPa) effects characteristic changes of motoric behaviour in adult rats. We observed a posthypoxic increase of spontaneous locomotion and of open-field activity. 24 h after hypoxic exposure the locomotion stimulated by dopaminergic agonists apomorphine or amphetamine was strengthened. Dopaminergic nuclei showed a different sensitivity to unilaterally applied dopamine after hypoxic exposure. Rotational behaviour was facilitated in the nucleus accumbens but significantly decreased in the substantia nigra. In the nucleus caudatoputamen we could not prove changes in comparison to controls. These results indicate that central dopaminergic processes are influenced by hypobaric hypoxic exposure. Besides the sensitization of dopaminergic receptor populations these changes of motoric behaviour may be connected with interactions between different transmitter systems or displacement of central regulation systems.