2001). Because relapse to cocaine-seeking behavior can occur even after a prolonged period of abstinence, one wonders whether repeated cocaine exposures would induce a longer-lasting potentiation of VTA DA neurons. Surprisingly, even when rats were administered non-contingent cocaine injections across for 7 consecutive days (Borgland et al. 2004), the duration of LTP onto VTA DA neurons was not increased and returned to baseline levels after 10 days of abstinence. Thus, despite repeated cocaine exposure, the short-lived potentiation of glutamatergic synapses suggests that cocaine-induced synaptic changes in VTA DA neurons represent a transient neuroadaptation to cocaine exposure.
