Neuroscience
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We have previously shown that the ability of buprenorphine to activate the opioid receptor-like (ORL1) receptor compromises its antinociceptive effect. Furthermore, morphine has been shown to alter the level of orphanin FQ/nociceptin (OFQ/N), the endogenous ligand of the ORL1 receptor, raising the possibility that the endogenous OFQ/N/ORL1 receptor system may be involved in the actions of these opioids. Thus, using mice lacking the ORL1 receptor and their wild-type littermates, the present study assessed the role of the ORL1 receptor in psychomotor stimulant and rewarding actions of buprenorphine and morphine. ⋯ Further, single conditioning with buprenorphine (3 mg/kg) induced place preference in mutant mice but not in their wild-type littermates. The results of binding assay showed that buprenorphine concentration-dependently (0-1000 nM) displaced specific binding of [(3)H]-OFQ/N in brain membrane of wild-type mice. Together, the present results suggest that the ability of buprenorphine to interact with the ORL1 receptor modulates its acute motor stimulatory and rewarding effects.
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The expression of voltage-gated sodium channels is regulated at multiple levels, and in this study we addressed the potential for alternative splicing of the Na(v)1.2, Na(v)1.3, Na(v)1.6 and Na(v)1.7 mRNAs. We isolated novel mRNA isoforms of Na(v)1.2 and Na(v)1.3 from adult mouse and rat dorsal root ganglia (DRG), Na(v)1.3 and Na(v)1.7 from adult mouse brain, and Na(v)1.7 from neonatal rat brain. These alternatively spliced isoforms introduce an additional exon (Na(v)1.2 exon 17A and topologically equivalent Na(v)1.7 exon 16A) or exon pair (Na(v)1.3 exons 17A and 17B) that contain an in-frame stop codon and result in predicted two-domain, truncated proteins. ⋯ Here we show that the expression of Na(v)1.3 mRNA containing exons 17A and 17B is unchanged in mouse following peripheral nerve injury (axotomy), whereas total Na(v)1.3 mRNA expression is upregulated by 33% (P=0.003), suggesting differential regulation of the alternatively spliced transcripts. The alternatively spliced rodent exon sequences are highly conserved in both the human and chicken genomes, with 77-89% and 72-76% identities to mouse, respectively. The widespread conservation of these sequences strongly suggests an additional level of regulation in the expression of these channels, that is also tissue-specific.
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Anxiety states and anxiety-related behaviors appear to be regulated by a distributed and highly interconnected system of brain structures including the basolateral amygdala. Our previous studies demonstrate that exposure of rats to an open-field in high- and low-light conditions results in a marked increase in c-Fos expression in the anterior part of the basolateral amygdaloid nucleus (BLA) compared with controls. The neural mechanisms underlying the anatomically specific effects of open-field exposure on c-Fos expression in the BLA are not clear, however, it is likely that this reflects activation of specific afferent input to this region of the amygdala. ⋯ On the test day rats were either, 1) exposed to an open-field in low-light conditions (8-13 lux) for 15 min (OF); 2) briefly HA or 3) left undisturbed (control). We report that dual immunohistochemical staining for c-Fos and CTb revealed an increase in the percentage of c-Fos-immunopositive basolateral amygdaloid complex-projecting neurons in open-field-exposed rats compared with HA and control rats in the ipsilateral CA1 region of the ventral hippocampus, subiculum and lateral entorhinal cortex. These data are consistent with the hypothesis that exposure to the open-field arena activates an anxiety-related neuronal system with convergent input to the basolateral amygdaloid complex.
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Current cognitive models suggest that the processing of dynamic facial attributes, including social signals such as gaze direction and facial expression, involves the superior temporal sulcus, whereas the processing of invariant facial structure such as the individuals' identity involves the fusiform face area. Where facial attractiveness, a social signal that may emerge from invariant facial structure, is processed within this dual-route model of face perception is uncertain. Here, we present two studies. ⋯ Second, we performed a functional magnetic resonance imaging study in healthy subjects that included an implicit and explicit processing of facial attractiveness. We found increased neural activity when explicitly judging facial attractiveness within a number of cortical regions including the fusiform face area, but not the superior temporal sulcus, indicating a potential contribution of the fusiform face area to this judgment. Thus, converging neuropsychological and neuroimaging evidence points to a critical role of the inferior occipitotemporal cortex in the processing of facial attractiveness.
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Cytidine-5-diphosphocholine (CDP-choline or citicholine) is an essential molecule that is required for biosynthesis of cell membranes. In adult humans it is used as a memory-enhancing drug for treatment of age-related dementia and cerebrovascular conditions. However the effect of CDP-choline on perinatal brain is not known. ⋯ However significant increases in neurite length, branch points and total area occupied by the neurons were observed. We conclude that exogenous supplementation of CDP-choline during development causes stable changes in neuronal morphology. Significant increase in dendritic growth and branching of pyramidal neurons from the somatosensory cortex resulted in enlarging the surface area occupied by the neurons which we speculate will augment processing of sensory information.