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Receptor Distribution (receptor + distribution)
Selected AbstractsEffects of early seizures on later behavior and epileptogenicityDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 2 2004Gregory L. Holmes Abstract Both clinical and laboratory studies demonstrate that seizures early in life can result in permanent behavioral abnormalities and enhance epileptogenicity. Understanding the critical periods of vulnerability of the developing nervous system to seizure-induced changes may provide insights into parallel or divergent processes in the development of autism. In experimental rodent models, the consequences of seizures are dependent on age, etiology, seizure duration, and frequency. Recurring seizures in immature rats result in long-term adverse effects on learning and memory. These behavioral changes are paralleled by changes in brain connectivity, changes in excitatory neurotransmitter receptor distribution, and decreased neurogenesis. These changes occur in the absence of cell loss. Although impaired cognitive function and brain changes have been well-documented following early-onset seizures, the mechanisms of seizure-induced dysfunction remain unclear. MRDD Research Reviews 2004;10:101,105. © 2004 Wiley-Liss, Inc. [source] Evidence for species differences in the pattern of androgen receptor distribution in relation to species differences in an androgen-dependent behaviorDEVELOPMENTAL NEUROBIOLOGY, Issue 3 2002Brian K. Shaw Abstract Chickens (Gallus gallus domesticus) and Japanese quail (Coturnix japonica), two closely related gallinaceous bird species, exhibit a form of vocalization,crowing,which differs between the species in two components: its temporal acoustic pattern and its accompanying postural motor pattern. Previous work utilizing the quail-chick chimera technique demonstrated that the species-specific characteristics of the two crow components are determined by distinct brain structures: the midbrain confers the acoustic pattern, and the caudal hindbrain confers the postural pattern. Crowing is induced by androgens, acting directly on androgen receptors. As a strategy for identifying candidate neurons in the midbrain and caudal hindbrain that could be involved in crow production, we performed immunocytochemistry for androgen receptors in these brain regions in both species. We also investigated midbrain-to-hindbrain vocal-motor projections. In the midbrain, both species showed prominent androgen receptor immunoreactivity in the nucleus intercollicularis, as had been reported in previous studies. In the caudal hindbrain, we discovered characteristic species differences in the pattern of androgen receptor distribution. Chickens, but not quail, showed strong immunoreactivity in the tracheosyringeal division of the hypoglossal nucleus, whereas quail, but not chickens, possessed strong immunoreactivity in a region of the ventrolateral medulla. Some of these differences in hindbrain androgen receptor distribution may be related to the species differences in the postural component of crowing behavior. The results of the present study imply that the spatial distribution of receptor proteins can vary even between closely related species. Such variation in receptor distribution could underlie the evolution of species differences in behavior. © 2002 Wiley Periodicals, Inc. J Neurobiol 52: 203,220, 2002 [source] Vitamin D receptor distribution in intestines of domesticated sheep Ovis ammon f. ariesJOURNAL OF MORPHOLOGY, Issue 2 2008Katharina Riner Abstract The biologically active form of vitamin D, i.e., 1,25-dihydroxycholecalciferol or calcitriol, plays an important role in bone metabolism and calcium homeostasis, which is often disturbed at the onset of lactation in high milk-yielding domestic ruminants. Gene transcription is modulated via vitamin D receptors, but nongenomic effects of vitamin D via membrane receptors have also been described. In the intestines, vitamin D promotes calcium absorption via vitamin D receptors. Vitamin D receptors are of clinical relevance, but have not been systematically assessed within all segments of the intestine in any species. Thus, we present for the first time an immunohistochemical study of the distribution patterns of the vitamin D receptor protein in sheep, which may be the basis for present and future investigations on mineral homeostasis in domestic ruminants. Tissue probes of the intestines were collected from five lambs and five nonlactating and nonpregnant dams, fixed in formalin, embedded in paraffin, and used for the assessment of vitamin D receptor protein. Nuclear vitamin D receptor immunoreaction was scored semiquantitatively and exhibited a segment-specific distribution pattern. Goblet cells always were devoid of any vitamin D receptor immunoreaction. Surface epithelial cells and enterocytes of the crypt openings generally demonstrated only a weak immunoreaction. Basally and/or intermediately located crypt epithelial cells exhibited stronger immunoreactions in duodenum, jejunum, and colon descendens. This basal/intermediate to superficial gradient was most pronounced in the duodenum and less evident in jejunum and colon descendens and not observed in ileum and cecum. There were no age-dependent variations in vitamin D receptor protein expression. Results demonstrate that intestinal vitamin D receptor distribution patterns are segment-specific and strongest immunoreactions correlate with highest intestinal calcium absorptive activities, as reported in literature. Strong expression of vitamin D receptors within the lower half of crypts also suggests a role for calcitriol in epithelial differentiation and cellular homeostasis. J. Morphol., 2008. © 2007 Wiley-Liss, Inc. [source] Pseudo-placentational Endometrial Cysts in a BitchANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2010C. Bartel Summary Cystic alterations of the canine endometrium compromise reproduction and fertility of the bitch and may lead to life-threatening diseases, such as pyometra. Even without clinical evidence, reduction of the uterine lumen by cysts implicates disturbances during migration, nidation and development of the embryo. Several studies point to the high variability of morphology of uterine endometrial cysts but they lack detailed analyses of alterations. In the present study, immunohistochemistry was used to investigate the expression of steroid hormone receptors (oestrogen, progesterone), proliferation activity, inflammation and infection in the cystic affected tissue regions in contrast to the normal endometrium. Oestrogen receptor expression showed a high density of receptors throughout the surface epithelial cells, crypt epithelial cells, glandular epithelial cells and stromal cells of the normal endometrium as well as the cystic affected regions. Proliferation in the cysts was verified in the middle and basal cells of the crypts. Neither in the endometrium nor in the cysts inflammatory processes or evidence of infection could be detected. Furthermore, lectin histochemistry and electron microscopic methods showed that lectin binding patterns and cell morphology of internal epithelial lining and surface epithelium of the cysts can be used to characterize and distinguish different types of cystic alterations. Analogies between epithelial cells of the glandular chambers of the canine placenta and the cystic cellular morphology, steroid hormone receptor distribution as well as lectin binding patterns of the endometrial cysts, as observed in this study, suggest to introduce the term ,pseudo-placentational endometrial cysts'. [source] The significance of vitamin D for fish: a reviewAQUACULTURE NUTRITION, Issue 1 2010E.-J. LOCK Abstract Fish store large quantities of vitamin D in their liver and fat tissues, including the fat associated with muscle, and this makes fish an important dietary source of vitamin D. Fish do not synthesize vitamin D and are fully dependent on dietary sources to meet their requirement. Under natural circumstances planktonic vitamin D accumulates in the aquatic food chain. In aquaculture, formulated diets are used and vitamin D intake can be manipulated. The minimum dietary requirement for vitamin D has been established in several fish species. The role of vitamin D in fish physiology is still enigmatic. Till the 1970s there was consensus that fish accumulate but not metabolize vitamin D. There is substantial evidence now, four decades later, that fish have a vitamin D endocrine system with similar functions as in mammals. We here summarize the major characteristics of the fish vitamin D endocrine system. The hydroxylation of vitamin D to more polar metabolites, their plasma levels and protein-bound transport in blood plasma will be discussed. The vitamin D receptor profile, receptor distribution and responses to vitamin D are reviewed for the key target tissues (gill, intestine, kidney and bone). We will address the classical slower actions through transcription factors as well as the faster G-protein coupled (membrane) receptor mediated effects. We then review the dietary requirement of vitamin D in aquaculture and address some lesser known functions of the vitamin D endocrine system. [source] Emerging pharmacology and physiology of neuromedin U and the structurally related peptide neuromedin SBRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2009JD Mitchell Neuromedin U (NMU) has been paired with the G-protein-coupled receptors (GPRs) NMU1 (formely designated as the orphan GPR66 or FM-3) and NMU2 (FM-4 or hTGR-1). Recently, a structurally related peptide, neuromedin S (NMS), which shares an amidated C-terminal heptapeptide motif, has been identified in both rat and human, and has been proposed as a second ligand for these receptors. Messenger RNA encoding NMU receptor subtypes shows differential expression: NMU1 is predominantly expressed in peripheral tissues, particularly the gastrointestinal tract, whereas NMU2 is abundant within the brain and spinal cord. NMU peptide parallels receptor distribution with highest expression in the gastrointestinal tract and specific structures within the brain, reflecting its major role in the regulation of energy balance. The NMU knockout mouse has an obese phenotype and, in agreement, the Arg165Trp amino acid variant of NMU-25 in humans, which is functionally inactive, co-segregated with childhood-onset obesity. Emerging physiological roles for NMU include vasoconstriction mediated predominantly via NMU1 with nociception and bone remodelling via NMU2. The NMU system has also been implicated in the pathogenesis of septic shock and cancers including bladder carcinoma and acute myeloid leukaemia. Intriguingly, NMS is more potent at NMU2 receptors in vivo where it has similar central actions in suppression of feeding and regulation of circadian rhythms to NMU. Taken together with its vascular actions, NMU may be a functional link between energy balance and the cardiovascular system and may provide a future target for therapies directed against the disorders that comprise metabolic syndrome. [source] Oxytocin and vasopressin receptor distributions in a solitary and a social species of tuco-tuco (Ctenomys haigi and Ctenomys sociabilis)THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 6 2008Annaliese K. Beery Abstract The neuropeptides oxytocin and vasopressin and their receptors have been implicated in elements of mammalian social behavior such as attachment to mates and offspring, but their potential role in mediating other types of social relationships remains largely unknown. We performed receptor autoradiography to assess whether forebrain oxytocin receptor (OTR) or vasopressin V1a receptor (V1aR) distributions differed with social structure in two closely related and ecologically similar species of South American rodents, the colonial tuco-tuco (Ctenomys sociabilis) and the Patagonian tuco-tuco (Ctenomys haigi). Long-term field studies have revealed that C. haigi is solitary, whereas C. sociabilis is social and provides a model of female-based group living. Our analyses revealed marked differences in OTR and V1aR distributions between these species. For example, only C. sociabilis had OTR binding in the piriform cortex and thalamus and V1aR binding in the olfactory bulbs. In contrast, C. haigi exhibited dramatically higher levels of OTR binding throughout the lateral septum and hippocampus. More generally, the group-living C. sociabilis exhibited a pattern of nucleus accumbens OTR and ventral pallidum V1aR binding different from that associated with the formation of opposite-sex pair bonds in microtine rodents. Higher binding in the central nucleus of the amygdala of C. sociabilis was consistent with the hypothesis that formation of social groups in C. sociabilis may be facilitated by reduced social anxiety. Low OTR binding in the lateral septum might also be a permissive factor for group living in C. sociabilis. Future studies will expand on these analyses to explore interspecific differences in ctenomyid receptor binding patterns in a phylogenetic context. J. Comp. Neurol. 507:1847,1859, 2008. © 2008 Wiley-Liss, Inc. [source] Extraordinary diversity in vasopressin (V1a) receptor distributions among wild prairie voles (Microtus ochrogaster): Patterns of variation and covariationTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 4 2003Steven M. Phelps Abstract The vasopressin V1a receptor is a gene known to be central to species differences in social behavior, including differences between the monogamous prairie vole and its promiscuous congeners. To examine how individual differences compare with species differences, we characterize variability in the expression of the vasopressin V1a receptor (V1aR) in a large sample of wild prairie voles. We find a surprising degree of intraspecific variation in V1aR binding that does not seem attributable to experimental sources. Most brain regions exhibit differences between upper and lower quartiles that are comparable to differences between species in this genus. Regions that are less variable have been implicated previously in regulating monogamous behaviors, suggesting that the lack of variation at these sites could reflect natural selection on mating system. Many brain regions covary strongly. The overall pattern of covariation reflects the developmental origins of brain regions. This finding suggests that shared mechanisms of transcriptional regulation may limit the patterns of gene expression. Such biases may shape both the efficacy of selection and the pattern of individual and species differences. Overall, our data indicate that the prairie vole would be a useful model for exploring how individual differences in gene expression influence complex social behaviors. J. Comp. Neurol. 466:564,576, 2003. © 2003 Wiley-Liss, Inc. [source] | ||||||||||