Contribution of central 5-HT2 receptors in the occurrence of locomotor activity and myoclonia in freely moving rats exposed to high pressure.

Helium pressure of more than 20 bar is a well known cause of neuroexcitatory changes, referred to as the high pressure neurological syndrome. In rodents, symptoms include myoclonia and locomotor activity. In the present study, we used the 5-HT2A receptor antagonist ketanserin and the 5-HT2C receptor agonist m-CPP to investigate the role of central 5-HT2 receptors in the occurrence of these symptoms. Results suggest that 5-HT2A receptors and 5-HT2C receptors would play a crucial role in the development of myoclonia and locomotor activity, respectively. The selectivity of the drugs used, and the central origin of both myoclonia and locomotor activity are discussed.