Pharmacology, biochemistry, and behavior
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Pharmacol. Biochem. Behav. · Jan 2012
Effect of ketamine on exploratory behaviour in BALB/C and C57BL/6 mice.
In this study, we evaluated the effect of ketamine on exploratory locomotion behaviours in the Balb/c and C57BL/6 strains of mice, which differ in their locomotion behaviours. Intraperitoneal administration of ketamine at three different doses (1, 5 or 10 mg/kg, 0.1 ml/10 gr body weight) was performed on adult male Balb/c and C57BL/6 mice. The same volume of saline was applied to the control group. ⋯ A subanaesthetic dose of ketamine increased exploratory locomotion in Balb/c mice. In contrast, a subanaesthetic dose of ketamine decreased exploratory locomotion in C57BL/6 mice. In conclusion, hereditary factors may play an important role in ketamine-induced responses.
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Pharmacol. Biochem. Behav. · Jan 2012
A role for 5-HT1A receptors in the basolateral amygdala in the development of conditioned defeat in Syrian hamsters.
The basolateral nucleus of the amygdala (BLA) is a key brain region regulating behavioral changes following stressful events, including social defeat. Previous research has shown that activation of serotonin (5-HT) 1A receptors in the BLA reduces conditioned fear and anxiety-like behavior. The objective of this study was to test whether 5-HT1A receptors in the BLA contribute to conditioned defeat in male Syrian hamsters (Mesocricetus auratus). ⋯ However, injection of WAY-100635 into the BLA did not alter the acquisition or expression of conditioned defeat. These data indicate that pharmacological activation of 5-HT1A receptors in the BLA is sufficient to impair the acquisition and expression of conditioned defeat. Our results suggest that pharmacological treatments that activate 5-HT1A receptors in the BLA are capable of reducing the development of stress-induced changes in behavior.
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Pharmacol. Biochem. Behav. · Dec 2011
Stimulation of the occipital or retrosplenial cortex reduces incision pain in rats.
The electrical stimulation of the occipital (OC) or retrosplenial (RSC) cortex produces antinociception in the rat tail-flick and formalin tests. This study examined the antinociceptive effects of stimulating the OC or RSC in a rat model of post-incision pain. The involvement of the anterior pretectal nucleus (APtN) as intermediary for the effect of OC or RSC stimulation was also evaluated because the OC and RSC send inputs to the APtN, which is implicated in antinociception and nociception. ⋯ The effects of stimulating the OC or RSC were not changed in rats treated with atropine. We conclude that stimulation-induced antinociception from the RSC or OC in rat post-incision pain activates distinct descending pain inhibitory pathways. The pathway activated from the RSC utilizes serotonergic and opioid mediation in the APtN, whereas stimulation of the OC utilizes a non-serotonergic, non-cholinergic and non-opioid mediation in the same nucleus.
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Pharmacol. Biochem. Behav. · Dec 2011
Intra-accumbal NMDA but not AMPA/kainate receptor antagonist attenuates WIN55,212-2 cannabinoid receptor agonist-induced antinociception in the basolateral amygdala in a rat model of acute pain.
Previous studies showed the role of basolateral amygdala (BLA) in cannabinoid-induced antinociception. Several lines of evidence indicated that the nucleus accumbens (NAc) receives excitatory glutamatergic inputs primarily from limbic-related structures, including the hippocampus, BLA, and various thalamic nuclei. Additionally, it has been shown that the NAc plays an important role in mediating the suppression of animal models of pain. ⋯ Nonetheless, administration of AMPA/kainate receptor antagonist, CNQX, could not affect WIN-induced analgesia. Additionally, solely administration of intra-accumbal injection of CNQX (2.5 μg/0.5 μl DMSO), but not AP5 (5 μg/0.5 μl saline), could significantly change the baseline tail-flick latencies in the rats. It seems that NMDA receptors located in the NAc, in part, mediate the antinociceptive responses of cannabinoid within the BLA in acute model of pain.
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Pharmacol. Biochem. Behav. · Nov 2011
Comparative StudyMaternal prolactin inhibition at the end of lactation affects learning/memory and anxiety-like behaviors but not novelty-seeking in adult rat progeny.
Maternal hypoprolactinemia at the end of lactation in rats reduces milk production and is associated with offspring's malnutrition. Since malnutrition during development is also known to have long lasting effects on cognition and emotion, in the present study we tested the hypothesis that maternal hypoprolactinemia, induced by bromocriptine treatment, at the end of the lactating period affects memory/learning, novelty-seeking and anxiety-like behaviors in adult male Wistar rats using, respectively, the radial arm water maze (RAWM), the hole board (HB) arena and the elevated plus-maze (EPM). We also analyzed serum corticosterone and thyroid hormone levels at postnatal day (PN) 21. ⋯ No difference was observed between groups regarding the number of nose-pokes in the HB. In the EPM, BRO rats stayed less time in and had fewer entries into the open-arms than CON ones. This pattern of results indicates that maternal bromocriptine treatment at the end of the lactating period results in poorer memory/learning performance and in higher levels of anxiety-like behavior in the adult offspring, demonstrating that even a relatively short period of malnutrition during development can have long lasting detrimental effects regarding cognition and emotion.