James E. Smith

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 Studies indicate that nucleus accumbens (NAcc) dopamine neurotransmission is involved in the reinforcing and direct effects of cocaine. The present study was initiated to explore further the relationship of NAcc extracellular dopamine concentrations ([DA]e) and cocaine self-administration using a yoked littermate design. In the first experiment, one rat(More)
Neuronal systems involved in the initiation of cocaine reinforcement were investigated by identifying brain sites where direct application of the drug was reinforcing. This was accomplished by allowing rats to self-administer picomolar concentrations of cocaine into discrete brain regions. The medial prefrontal cortex supported self-administration, while(More)
Neuronal systems involved in the initiation of reinforcement following the response-contingent delivery of cocaine into the medial prefrontal cortex were investigated. Dose-effect analyses demonstrated that different concentrations of cocaine result in distinguishable patterns of self-administration which could be empirically determined by measuring the(More)
In the rat, approximately 20% of total body heat-loss occurs by sympathetically mediated increases in blood flow through an elaborate system of arteriovenous anastomoses in the skin of its tail. In this study, the CNS cell groups that regulate this sympathetic outflow were identified by the viral transneuronal labeling method. Pseudorabies virus was(More)
The drug self-administration paradigm is routinely used to assess the abuse liability of psychoactive compounds. Investigations of the behavioral effects of drug use, however, often involve the response-independent (experimenter-delivered) administration of the compound. It is frequently assumed that response-independent presentation of a compound has the(More)
Microinfusions of the endogenous opiate neurohumor, methionine enkephalin, into the nucleus accumbens initiated a reinforcing stimulus in a dose-related manner. The reinforcing nature of this intracranial self-administration was evaluated with intermittent schedules of reinforcement and a two-lever discrimination procedure. Opiate receptors are likely(More)
Dopaminergic innervations of the nucleus accumbens (NAcc) have a significant role in the brain processes underlying the reinforcing actions of abused drugs. In addition to the evidence from selective lesions and receptor antagonists, recent determinations of increased extracellular dopamine concentrations ([DA]e) in this structure during cocaine and ethanol(More)
Three experiments, using 344 pigs, were conducted to evaluate the influence of beta-glucan on growth performance, neutrophil and macrophage function, haptoglobin production, and resistance to Streptococcus suis challenge in weanling pigs. In Exp. 1, 144 pigs were used to evaluate the influence of .1% dietary beta-glucan in a soybean meal- or milk(More)