Project 10

Cannabinoid receptor and glucocorticoid receptor interactions in prepulse inhibition of the startle reflex.

Prior research from this lab has demonstrated that cannabinoid agonists can either increase or decrease prepulse inhibition of the startle reflex in rats, depending on whether or not there is co-activation of glucocorticoid receptors. Since patients with schizophrenia exhibit decreases in prepulse inhibition, but also tend (as a group) to more frequently use cannabis, it is hypothesised that cannabis may paradoxically both act as self-medication (ie. increase prepulse inhibition) and worsen (decrease prepulse inhibition) as a function of level of stress. However, it has not yet been established for certain which cannabinoid receptor (CB1 – brain) or CB2 (immune system) is responsible for these effects. Both systems involve the stress- glucocorticoid system. This project will use antagonists selective for the CB1 and CB2 receptors to determine the receptors responsible.