Opposite effects of typical and atypical anti-psychotic drugs on sensitized dopamine receptors: Sub-chronic low dose Olanzapine exposure reverses sensitization but a similar regimen of low dose haloperidol potentiates sensitization effects

Abstract

The profound differences observed between typical and atypical antipsychotic exposure in animals with an upregulated dopamine system are consistent with clinical evidence for lower risk of psychomotor disturbances with chronic treatment with atypical antipsychotic. Importantly, the finding that a very low dose of olanzapine reversed sensitization effects suggests that low-dose olanzapine may have clinical utility in a variety of disorders linked to sensitization of the dopamine system.

Neuropharmacology of light-induced locomotor activation

“…Given that D2-and D3-receptors may have opposing roles in LIA at the level of single brain areas (Fernandes et al, 2012); it cannot be ruled out that also at systemic levels D2-and D3-receptor effects cancelled each other out in the action of haloperidol. Small, D2-autoreceptor preferring doses of haloperidol were found to have behavioural facilitating effects (Dias et al, 2013). From present findings one cannot rule out distinct involvement of pre-and postsynaptic D2-receptors in LIA, which may be cancelled out when both populations get activated simultaneously.…”