RESUMEN
Intracranial self-administration of drugs offers the opportunity to localize the neuronal substrates mediating the rewarding effects of drugs. The purpose of the present study was to explore whether the nucleus accumbens shell and the central nucleus of the amygdala, two components of the "extended amygdala," would support self-administration of the psychostimulant amphetamine. Male Wistar rats were trained to lever press under a Fixed Ratio 1 schedule of reinforcement for D-amphetamine injections (0, 1.0, 1.5, 2.0 and 3.0 microg/microl/inj) into either the nucleus accumbens shell or the central nucleus of the amygdala. An ascending limb dose-response function with peak responding at the 2.0 microg/microl/inj dose was obtained for self-administration at both brain sites. These results indicate that monoaminergic transmission in both the nucleus accumbens shell and the central nucleus of the amygdala mediates the rewarding effects of amphetamine. Further, the present study provides additional evidence about the functional homogeneity of the forebrain continuum called the "extended amygdala."
Asunto(s)
Anfetamina/administración & dosificación , Amígdala del Cerebelo/efectos de los fármacos , Amígdala del Cerebelo/fisiología , Núcleo Accumbens/efectos de los fármacos , Animales , Inhibidores de Captación de Dopamina/administración & dosificación , Relación Dosis-Respuesta a Droga , Masculino , Núcleo Accumbens/fisiología , Ratas , Ratas Wistar , Autoadministración/métodos , Autoadministración/psicologíaRESUMEN
Neuroscience research projects often use intracranial (IC) microinfusions to target drug delivery to specific brain areas during behavioral testing. These experiments require accurate and precisely-timed delivery of small volumes. We present here a stepper motor-powered micropump assembly for such delivery. This system is hands-free, does not use a potentially leaky fluid swivel or use long delivery tubes that are subject to peristaltic forces during animal movements, and has been applied in combination with other paradigms. This micropump system reliably delivers a wide range of fluid volumes (e.g. 50 nL to 1 microL in tissue or greater for intraventricular injections) bilaterally from two independent, commercially available microsyringes through standard surgically implanted guide cannulae. It is easy to build and disassemble for cleaning or changing microsyringes. This system can also be used for a variety of purposes, e.g. intracranial self-administration, place conditioning, and many more, with the advantage that it provides a way to gather important data in the seconds and minutes following IC microinfusion without disruption of the animal's behavior by handling.