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Brain Distribution (brain + distribution)
Selected AbstractsBrain distribution of myosin Va in rainbow trout Oncorhynchus mykissACTA ZOOLOGICA, Issue 1 2008Kátia Gisele Oliveira Rancura Abstract This study presents data on myosin Va localization in the central nervous system of rainbow trout. We demonstrate, via immunoblots and immunocytochemistry, the expression of myosin Va in several neuronal populations of forebrain, midbrain, hindbrain and spinal cord. The neuronal populations that express myosin Va in trout constitute a very diverse group that do not seem to have many specific similarities such as neurotransmitters used, cellular size or length of their processes. The intensity of the immunoreactivity and the number of immunoreactive cells differ from region to region. Although there is a broad distribution of myosin Va, it is not present in all neuronal populations. This result is in agreement with a previous report, which indicated that myosin Va is approximately as abundant as conventional myosin II and kinesin, and it is broadly involved in neuronal motility events such as axoplasmatic transport. Furthermore, this distribution pattern is in accordance with what was shown in rats and mice; it indicates phylogenetic maintenance of the myosin Va main functions. [source] Blood,brain barrier damage and brain penetration of antiepileptic drugs: Role of serum proteins and brain edemaEPILEPSIA, Issue 4 2009Nicola Marchi Summary Purpose:, Increased blood,brain barrier (BBB) permeability is radiologically detectable in regions affected by drug-resistant epileptogenic lesions. Brain penetration of antiepileptic drugs (AEDs) may be affected by BBB damage. We studied the effects of BBB damage on brain distribution of hydrophilic [deoxy-glucose (DOG) and sucrose] and lipophilic (phenytoin and diazepam) molecules. We tested the hypothesis that lipophilic and hydrophilic drug distribution is differentially affected by BBB damage. Methods:, In vivo BBB disruption (BBBD) was performed in rats by intracarotid injection of hyperosmotic mannitol. Drugs (H3-sucrose, 3H-deoxy-glucose, 14C-phenytoin, and C14-diazepam) or unlabeled phenytoin was measured and correlated to brain water content and protein extravasation. In vitro hippocampal slices were exposed to different osmolarities; drug penetration and water content were assessed by analytic and densitometric methods, respectively. Results:, BBBD resulted in extravasation of serum protein and radiolabeled drugs, but was associated with no significant change in brain water. Large shifts in water content in brain slices in vitro caused a small effect on drug penetration. In both cases, total drug permeability increase was greater for lipophilic than hydrophilic compounds. BBBD reduced the amount of free phenytoin in the brain. Discussion:, After BBBD, drug binding to protein is the main controller of total brain drug accumulation. Osmotic BBBD increased serum protein extravasation and reduced free phenytoin brain levels. These results underlie the importance of brain environment and BBB integrity in determining drug distribution to the brain. If confirmed in drug-resistant models, these mechanisms could contribute to drug brain distribution in refractory epilepsies. [source] ORIGINAL RESEARCH,BASIC SCIENCE: Neuroanatomical Evidence for a Role of Central Melanocortin-4 Receptors and Oxytocin in the Efferent Control of the Rodent Clitoris and VaginaTHE JOURNAL OF SEXUAL MEDICINE, Issue 6 2010Helene Gelez PhD ABSTRACT Introduction., The clitoris and the vagina are the main peripheral anatomical structures involved in physiological changes related to sexual arousal and orgasm. Their efferent control and, more particularly, the neurochemical phenotype of these descending neuronal pathways remain largely uncharacterized. Aim., To examine if brain neurons involved in the efferent control of the clitoris and the vagina possess melanocortin-4 receptor (MC4-R) and/or contain oxytocin (OT). Methods., Neurons involved in the efferent control of the vagina and clitoris were identified following visualization of pseudorabies virus (PRV) retrograde tracing. PRV was injected into the vagina and clitoris in adult rats in estrous. On the fifth day postinjection, animals were humanely sacrificed, and brains were removed and sectioned, and processed for PRV visualization. The neurochemical phenotype of PRV-positive neurons was identified using double or triple immunocytochemical labeling against PRV, MC4-R, and OT. Double and triple labeling were quantified using confocal laser scanning microscopy. Main Outcome Measure., Neuroanatomical brain distribution, number and percentage of double-labeled PRV/MC4-R and PRV-/OT-positive neurons, and triple PRV-/MC4-R-/OT-labeled neurons. Results., The majority of PRV immunopositive neurons which also expressed immunoreactivity for MC4-R were located in the paraventricular and arcuate nuclei of the hypothalamus. The majority of PRV positive neurons which were immunoreactive (IR) for OT were located in the paraventricular nucleus (PVN), medial preoptic area (MPOA), and lateral hypothalamus. PRV positive neurons were more likely to be IR for MC4-R than for OT. Scattered triple-labeled PRV/MC4-R/OT neurons were detected in the MPOA and the PVN. Conclusion., These data strongly suggest that MC4-R and, to a less extent, OT are involved in the efferent neuronal control of the clitoris and vagina, and consequently facilitate our understanding of how the melanocortinergic pathway regulates female sexual function. Gelez H, Poirier S, Facchinetti P, Allers KA, Wayman C, Alexandre L, and Giuliano F. Neuroanatomical evidence for a role of central melanocortin-4 receptors and oxytocin in the efferent control of the rodent clitoris and vagina. J Sex Med 2010;7:2056,2067. [source] Potentiation of domperidone-induced catalepsy by a P-glycoprotein inhibitor, cyclosporin ABIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 3 2003Kenji Tsujikawa Abstract The distribution of domperidone (DOM), a peripheral dopamine D2 receptor antagonist, to the brain is restricted by P-glycoprotein (P-gp) at the blood,brain barrier (BBB) and for this reason, DOM rarely causes parkinsonian symptoms, such as extrapyramidal side effects (EPS), unlike other dopamine D2 antagonists. In this study, we aimed to investigate whether cyclosporin A (CsA), a P-gp inhibitor, potentiates EPS induced by DOM. The intensity of EPS was assessed in terms of the duration of catalepsy in mice. D1, D2 and mACh receptor occupancies at the striatum were measured in vivo and in vitro. Moreover, the distribution of DOM to the brain was investigated by using an in situ brain perfusion technique. The intensity of DOM-induced catalepsy was significantly potentiated by the coadministration of CsA. The in vivo occupancies of D1, D2 and mACh receptors, as well as the brain distribution of DOM, were increased by CsA. These results suggest that CsA increases the brain distribution of DOM by inhibiting P-gp at the BBB, and potentiates catalepsy by increasing the occupancies of the D1 and D2 receptors. The risk of DOM-induced parkinsonism may be enhanced by the coadministration of CsA. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||