Rationale: The intake of psychostimulant drugs may induce cognitive dysfunction and negative affective-like states, and is associated with increased activity of stress-responsive systems. The corticotropin-releasing factor (CRF) system mediates neuroendocrine, behavioural and autonomic responses to stressors, and might be implicated in substance-related disorders. CRF signalling is mediated by two receptor types, named CRF1 and CRF2.
Objectives: The present study aims to elucidate the role for the CRF1 receptor in cognitive dysfunction and anxiety-like states induced by cocaine.
Results: The genetic inactivation of the CRF1 receptor (CRF1+/- and CRF1-/-) does not influence recognition memory in drug-naïve mice, as assessed by the novel object recognition (NOR) test. Moreover, the chronic administration of escalating doses of cocaine (5-20 mg/kg, i.p.) induces NOR deficits, which are unaffected by CRF1 receptor-deficiency. However, the same drug regimen reveals an anxiety-like vulnerability to cocaine in CRF1-/- but not in wild-type or CRF1+/- mice, as assessed by the elevated plus maze test.
Conclusions: The present findings indicate dissociation of cognitive dysfunction and anxiety-like states induced by cocaine. Moreover, they unravel a novel mechanism of vulnerability to psychostimulant drugs.