Alberto José Ramírez Valadez

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Interactions between caffeine and cocaine have been demonstrated in a number of behavioral paradigms. The present study was undertaken in an attempt to determine whether caffeine could reinstate extinguished cocaine-taking behavior in rats. Experienced self-administering rats were first put through extinction training. The rats were then given an injection(More)
Acquisition of cocaine self-administration (0.125, 0.25 or 0.5 mg/kg/infusion) was assessed in rats that had received prior exposure to either saline or amphetamine (2.0 mg/kg). Acquisition of self-administration was dose-dependent, with the highest dose leading to the shortest latency to reliably discriminate between depression of a lever that resulted in(More)
Previously, we demonstrated that caffeine dose-dependently reinstated extinguished cocaine-taking behavior in rats. In the present study, we determined whether this effect of caffeine would extinguish with repeated exposures. Rats were first trained to self-administered cocaine intravenously. Once reliable self-administration was obtained, the pumps that(More)
This study assessed the enduring effects of amphetamine preexposure on the subsequent reinforcing effects of cocaine. Rats received nine daily injections of either d-amphetamine SO4 (2.0 mg/kg, IP) or vehicle 45 days prior to testing of the acquisition of cocaine (0.25 mg/kg/infusion) self-administration. The latency to acquire reliable cocaine(More)
This study assessed the ability of cocaine to increase synaptic levels of dopamine (DA) in the ventral striatum (VS) and medial prefrontal cortex (mPFC) following repeated daily exposure to amphetamine or nicotine. In vivo microdialysis was used to assay DA levels in the awake freely moving male Sprague-Dawley rats. Three days following guide cannula(More)
Shadow Mapping is a reliable technique to produce shadows in a scene in real time. This technique has been mostly applied to directional lights and only a few methods have used it for omnidirectional lighting [Brabec et al. 2002]. These methods need more than one full render pass to compute the whole shadow mapping. In this work we propose an approach to(More)
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