Synthetic cathinones, otherwise known as “bath salts”, have gained significant attention in the last few years as a result of increased use and abuse. One such compound, 3,4-methylenedioxypyrovalerone (MDPV), is pharmacologically and behaviorally similar to cocaine and has been shown to possess both aversive and rewarding effects. For a host of other drugs, each of these effects (and their relative balance) can be influenced by a variety of factors, including sex, which in turn impacts drug taking behavior. In this context, the present assessment sought to determine whether males and females differed in MDPV-induced CTA and CPP. Both male and female Sprague-Dawley rats underwent a combined CTA/CPP procedure, in which an injection of one of three doses of MDPV (1.0, 1.8 or 3.2 mg/kg) was paired with both a novel saccharin solution and a novel environment and changes in preferences for these stimuli were examined. Taste avoidance was evident in both sexes, although this avoidance was weaker in females compared to males. MDPV also produced place preferences in all drug-treated animals, but these preferences did not vary as a function of sex. The fact that females showed a weaker avoidance response compared to males (despite comparable preferences) suggests that females may have a heightened susceptibility to use and abuse of MDPV, paralleling results seen with cocaine and other stimulants. The present findings extend the behavioral characterization of MDPV and the factors that may alter its aversive and rewarding effects.

Adolescent rats are more sensitive to the rewarding and less sensitive to the aversive properties of various drugs of abuse than their adult counterparts. Given a nationwide increase in use of “bath salts,” the present experiment employed the conditioned taste aversion procedure to assess the aversive effects of 3,4-methylenedioxypyrovalerone (MDPV; 0, 1.0, 1.8 or 3.2 mg/kg), a common constituent in “bath salts,” in adult and adolescent rats. As similar drugs induce thermoregulatory changes in rats, temperature was recorded following MDPV administration to assess if thermoregulatory changes were related to taste aversion conditioning. Both age groups acquired taste aversions, although these aversions were weaker and developed at a slower rate in the adolescent subjects. Adolescents increased and adults decreased body temperature following MDPV administration with no correlation to aversions. The relative insensitivity of adolescents to the aversive effects of MDPV suggests that MDPV may confer an increased risk in this population.

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OBJECTIVE Most drugs of abuse have both aversive and rewarding effects, and the use and abuse potential of such drugs is thought to be a function of a balance of these affective properties. Characterizing these effects and their relative balance may provide insight into abuse vulnerability. One drug that has received recent attention is methylenedioxyparavalerone (MDPV), a monoamine transport inhibitor similar to, but significantly more potent than, cocaine. MDPV is self-administered and has been shown to produce aversive and rewarding effects in adult rats. The present study extended this characterization of the affective properties of MDPV by examining its ability to support place conditioning at a range of doses known to produce taste avoidance. METHODS Male Sprague-Dawley rats were injected with MDPV (1, 1.8 or 3.2 mg/kg) or saline and placed on the non-preferred side of a place conditioning apparatus for 30 min. On the next day, they were given an injection of saline and placed on the preferred side. This was repeated three times for a total of four conditioning cycles, and side preference was assessed on a final test. RESULTS All doses of MDPV produced significant increases in time spent in the drug-paired chamber, an effect not seen in vehicle-treated animals. CONCLUSIONS That the same doses of MDPV induced both taste avoidance and place preference allows assessments of how other factors might impact these effects and how they may, in turn, contribute to its abuse liability.

Despite widespread cannabis use in humans, few rodent models exist demonstrating significant Δ⁹-tetrahydrocannabinol (THC) self-administration, possibly due to THC's co-occurring aversive effects, which impact drug reinforcement. Cannabis contains a number of phytocannabinoids in addition to THC, one of which, cannabidiol (CBD), has been reported to antagonize some of the aversive effects of THC. Given such effects of CBD, it is possible that it might influence THC intravenous self-administration in rodents. Accordingly, male and female Long-Evans rats were trained to self-administer THC over a 3-week period and then were assessed for the effects of CBD on responding for THC at 1:1 and 1:10 dose ratios or for the establishment of cocaine self-administration (as a positive control for drug self-administration). Consistent with previous research, THC self-administration was modest and only evident in a subset of animals (and unaffected by sex). Cocaine self-administration was high and evident in the majority of animals tested, indicating that the design was sensitive to drug reinforcement. There was no effect of CBD pretreatment on THC intravenous self-administration at any CBD:THC dose ratio. Future developments of animal models of THC self-administration and the examination of factors that affect its display remain important to establish procedures designed to assess the basis for and treatment of cannabis use and abuse. (PsycINFO Database Record