Learn More
Accumulating evidence indicates that an animal's response to a drug can be profoundly affected by early environmental influences. The brain opioid and dopamine systems may play a critical role in these effects, since various types of stress and drugs of abuse promote alterations in these brain systems. To study this further, we investigated long-term(More)
Recently, we have shown that rats repeatedly treated with ethanol and/or cocaine have decreased kappa-opioid receptor mRNA levels in the mesolimbic system. The aim of the present study was to investigate the short- and long-term effects of repeated ethanol administration on opioid peptide concentrations in brain tissue of male Sprague-Dawley rats. Dynorphin(More)
Opioid peptides were analysed in tissue extracts of various brain structures and the pituitary gland from rats sacrificed by microwave irradiation, and compared with peptide levels in tissue extracts from decapitated rats. Dynorphin A, dynorphin B and Leu-enkephalinArg6, derived from prodynorphin, and Met-enkephalinArg6Phe7 from proenkephalin, were(More)
Environmental manipulations early in life may induce persistent alterations in adult behaviour and physiology. The underlying neural mechanisms of these responses are not yet clear. We have previously reported long-term changes in brain opioid peptide levels in male and female Sprague-Dawley rats after short periods (15 min, known as neonatal handling) of(More)
The motivation to drink alcohol and the eventual risk of becoming addicted are in part genetically determined. Because opioid peptides are considered central to motivated behaviors, we have analyzed opioid peptides in relevant areas of the brain of two outbred lines of rats: the alcohol-preferring [Alko Alcohol (AA)] line who voluntarily drink alcohol and(More)
The vulnerability to develop alcoholism is dependent on both genetic and environmental factors. The neurobiological mechanisms underlying these factors are not fully understood but individual divergence in the endogenous opioid peptide system may contribute. We have previously reported that early-life experiences can affect endogenous opioids and also adult(More)
Stress early in life puts the individual at a greater risk for developing mental disorders in adulthood. The animal model of maternal separation involves daily removal of pups from their mother over the early postnatal period and leads to several behavioral deficits in adults. Since this period corresponds to a time of extensive developmental changes in the(More)
The effects of neonatal handling on the opioid dynorphin peptides in the brain and pituitary gland of Sprague-Dawley rats were investigated. Ten weeks after the neonatal handling, handled rats had higher tissue levels of dynorphin A and B in the hypothalamus, pituitary gland and striatum and slightly higher dynorphin B levels in the hippocampus, medulla(More)
The hippocampus plays a central role in the acquisition and storage of information. Long-term potentiation in the mossy fibre pathway to the CA3 region in the hippocampus, an animal model of memory acquisition, is modulated by dynorphin peptides. This study investigated the possible role of hippocampal dynorphin in spatial learning. Male rats were trained(More)
In vivo microdialysis was used to study the effect of intracerebral administration of dopamine agonists on dynorphin B release in the striatum and substantia nigra of rats. The release of dopamine and GABA was also investigated. Administration of the dopamine D1 agonist SKF 38393 (10-100 microM) into the striatum increased extracellular dynorphin B and GABA(More)