Behavioural and neurochemical assessment of salvinorin A abuse potential in the rat.
Psychopharmacology – January 01, 2015
Source: PubMed
Summary
Despite influencing brain dopamine, a key reward chemical, Salvinorin A appears to lack strong addictive properties. Researchers explored whether this hallucinogen could drive compulsive self-administration in rats and alter dopamine levels in the brain's reward center. They found that while systemic doses did increase dopamine, rats did not consistently choose to self-administer the drug intravenously. This suggests Salvinorin A may not sustain the stable drug-seeking behavior seen with other commonly abused substances.
Abstract
Salvinorin A is a recreational drug derived from Salvia divinorum, a sage species long used as an entheogen. While salvinorin A has potent hallucinogenic properties, its abuse potential has not been assessed consistently in controlled behavioural and neurochemical studies in rodents. This study aimed to assess salvinorin A abuse potential by measuring its capacity to establish and maintain self-administration behaviour and to modify dopamine (DA) levels in the nucleus accumbens (NAcc) of rats. Male Lister Hooded (LH) and Sprague-Dawley (SD) rats were allowed to self-administer salvinorin A (0.5 or 1.0 μg/kg/infusion) intravenously 2 h/day for 20 days under a continuous schedule of reinforcement and lever pressing as operandum. LH rats discriminated between the active and inactive levers but did not reach the acquisition criterion for stable self-administration (≥12 active responses vs ≤5 inactive responses for at least 5 consecutive days). SD rats discriminated between the two levers at the lower dose only but, like LH rats, never acquired stable self-administration behaviour. Systemic salvinorin A increased extracellular DA in the NAcc shell of both LH (at ≥40 μg/kg) and SD rats (at ≥5 μg/kg), but injection into the ventral tegmental area (VTA) induced no significant change in NAcc DA concentration in LH rats and only brief elevations in SD rats. Salvinorin A differs from other commonly abused compounds since although it affects accumbal dopamine transmission, yet it is unable, at least at the tested doses, to sustain stable intravenous self-administration behaviour.