Pharmacology, biochemistry, and behavior
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Treatment of postpartum female rats with morphine inhibits maternal behavior. The same type of treatment stimulates foraging in adult animals. The aim of the present study was to investigate, in lactating rats, the functional role of opioid systems in the choice between caring for pups versus hunting insects. ⋯ Consistently, naloxone treatment induced a decrease in number of insects captured and an increase in the percentage of animals displaying nursing behavior. These results provide important insight into the role of opioidergic transmission in the regulation of behavioral selection during lactation. The present results suggest that endogenous opioids may stimulate hunting by replacing maternal behavior during lactation.
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Pharmacol. Biochem. Behav. · Aug 2007
Evaluation of pain behavior and bone destruction in two arthritic models in guinea pig and rat.
The primary aim of the study was to describe and correlate pain behavior and changes in bone morphology in animal models of arthritis both in rats and guinea pigs. Either complete Freund's adjuvant (CFA) or mono-iodoacetate (MIA) solution was injected into the left knee joint to obtain a model for rheumatoid arthritis and osteoarthritis, respectively. Subsequently, animals were behaviorally tested during a period of 12 days after CFA injection and at least 19 days after MIA injection. ⋯ To evaluate bone destruction mu-computed tomography scans of the arthritic knee were taken on the last experimental day. Different bone parameters indicative of osteolysis and decreased trabecular connectivity were significantly correlated with the observed pain behavior. Detailed description of morphological changes in arthritic joints better characterizes the different animal models and might add to the knowledge on the working mechanisms of analgesic compounds that have an influence on bone structures in arthritis.
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Pharmacol. Biochem. Behav. · Aug 2007
The partial 5-HT(1A) agonist buspirone reduces the expression and development of l-DOPA-induced dyskinesia in rats and improves l-DOPA efficacy.
Dopamine (DA) replacement therapy with l-DOPA remains the standard pharmacotherapy for Parkinson's disease (PD). Unfortunately, chronic l-DOPA treatment is accompanied by development of motor fluctuations and l-DOPA-induced dyskinesia (LID). While serotonin (5-HT)(1A) agonists acutely reduce these complications, their prophylactic and long-term effects are not well-delineated. ⋯ AIMs and FAS were measured throughout. In l-DOPA-primed rats, buspirone dose-dependently reduced LID and improved l-DOPA-related motor performance due to action at the 5-HT(1A) receptor. In l-DOPA-naïve rats, buspirone delayed LID development while improving l-DOPA's anti-parkinsonian efficacy indicating the potential long-term benefits of 5-HT(1A) agonists for reduction of l-DOPA-related side effects.
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Pharmacol. Biochem. Behav. · May 2007
The impact of the opioids fentanyl and morphine on nociception and bone destruction in a murine model of bone cancer pain.
Chronic pain resulting from metastasis into skeleton of certain neoplastic diseases remains poorly understood and relatively resistant to analgesic treatment. Opioids are the principal axis in drug therapy for this type of pain, especially at the end stage of cancer. Our aim was to examine whether, fentanyl as well as morphine, two potent analgesic opioids commonly used to treat cancer pain, would inhibit pain and bone lesion-related responses in a murine model of bone cancer pain. ⋯ Both fentanyl and morphine treatments resulted in clear antinociceptive properties as well as reductions in cancer cell-induced bone lesions. The present results demonstrate that fentanyl, and to some lesser degree morphine, has potential benefits in the treatment and development of bone cancer pain. As such, chronic administration of high doses of certain opioids like fentanyl may have clinical utility in the management of bone cancer pain.
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Pharmacol. Biochem. Behav. · Mar 2007
NMDA receptor in conditioned flavor-taste preference learning: blockade by MK-801 and enhancement by D-cycloserine.
Conditioned flavor-taste preference (CFTP) is a robust form of learning in which animals acquire a preference for a flavor (e.g. Kool-Aid) previously mixed with a highly preferred tastant (e.g. fructose) over a flavor previously mixed with a less-preferred tastant (e.g. saccharin). Here, the role of the N-methyl-D-aspartate (NMDA) glutamate-glycine receptor (NR) was probed using systemic MK-801, a non-competitive antagonist, and D-cycloserine (DCS), a glycine agonist. ⋯ In contrast to MK-801, administration of DCS prior to conditioning enhanced CFTP learning (but not reversal conditioning). These results demonstrate that NR neurotransmission is critical for CFTP learning. Furthermore, enhancement of CFTP learning by DCS suggests that endogenous levels of glycine or D-serine may be a limiting factor in CFTP learning.