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PubMed1989

Effect of lifelong selenium and vitamin E deficiency or supplementation on pigment accumulation in rat peripheral tissues.

The accumulation of lipopigments during aging in several peripheral organs and in the nervous system is considered to be related to the peroxidation of unsaturated fatty acids. In this study the effect of lifelong (until to 18 months) dietary antioxidants selenium and vitamin-E on pigment accumulation in some peripheral tissues was estimated using fluorescence and electron microscopy. In the vitamin E deficiency group, there was increased pigment accumulation in all peripheral tissues studied except the hypogastric ganglion, where no change was observed. The vitamin E supplementation degreased the pigment accumulation in older animals in some of the tissues studied. At the electron microscopical level the accumulated pigment in the adrenal cortex showed a lipofuscin-like structure. Lifelong selenium supplementation or deficiency did not significantly alter pigment accumulation in any of the tissues studied. It is possible that in many organs dietary selenium may not play a critical role in lipofuscin formation.

Adrenal Glands↗
PubMed2000

Microdialysis in peripheral tissues.

The objective of this review is to survey the recent literature regarding the applications of microdialysis in pharmacokinetic studies and facilitating many other studies in peripheral tissues such as muscle, subcutaneous adipose tissue, heart, lung, etc. It has been reported extensively that microdialysis is a useful technique for monitoring free concentrations of compounds in extracellular fluid (ECF), and it is gaining popularity in pharmacokinetic and pharmacodynamic studies, both in experimental animals and humans. The first part of this review discusses the use of microdialysis technique for ECF sampling in peripheral tissues in animal studies. The second part of the review describes the use of microdialysis for ECF sampling in peripheral tissues in human studies. Microdialysis has been applied extensively to measure both endogenous and exogenous compounds in ECF. Of particular benefit is the fact that microdialysis measures the unbound concentrations in the peripheral tissue fluid which have been shown to be responsible for the pharmacological effects. With the increasing number of applications of microdialysis, it is obvious that this method will have an important place in studying drug pharmacokinetics and pharmacodynamics.

Adipose Tissue↗
PubMedDate not supplied

Splice variants of the OB receptor gene are differentially expressed in brain and peripheral tissues of mice.

A high affinity receptor for OB protein was recently cloned from the choroid plexus of mice. At least six alternatively spliced forms of the OB receptor (OB-R) gene have been described, all of which encode proteins containing the OB-R extracellular domain. One splice variant encodes a receptor with a long intracellular domain, OB-RL, that has been implicated in OB-R signaling. Here, we have used in situ hybridization to examine the localization of OB-R splice variants in brain and peripheral tissues of adult and newborn mice. Using a probe hybridizing with all known splice variants, we confirmed that OB-R mRNA was widely distributed in the adult tissues. In the CNS, choroid plexus was the major site of expression. We now demonstrate that OB-R mRNA is expressed in peripheral tissues; primarily associated with connective tissues. In addition, OB-R mRNA was detected at higher levels in peripheral tissues of newborn mice than in adult mice. With a probe specific for OB-RL, we confirmed that high mRNA expression was detected in hypothalamic nuclei, while low levels were observed in choroid plexus. We now report that in peripheral tissues of adult mice, OB-RL mRNA expression was either very low or undetectable. In newborn mice, the pattern of OB-RL message expression in the CNS was similar to that of adult mice, while bone was the site of highest OB-RL message expression in the peripheral tissue. These data suggest different biological roles for OB-R splice variants encoding the short and long forms of OB-R. The localization of OB-RL to hypothalamic nuclei supports the idea that OB-RL is the brain receptor that mediates OB protein signaling and actions. In addition, the expression of OB-R message in newborn mice also suggests a biological role of OB-R during development in mice.

Alternative Splicing↗
PubMed1987

Binding of [3H]Ro 5-4864 and [3H]PK 11195 to cerebral cortex and peripheral tissues of various species: species differences and heterogeneity in peripheral benzodiazepine binding sites.

The binding of [3H]PK 11195 and [3H]Ro 5-4864 to membrane preparations from cerebral cortex and peripheral tissues of various species was studied. [3H]PK 11195 (0.05-10 nM) bound with high affinity to rat and calf cerebral cortical and kidney membranes. [3H]Ro 5-4864 (0.05-30 nM) also successfully labeled rat cerebral cortical and kidney membranes, but in calf cerebral cortical and kidney membranes, its binding capacity was only 3 and 4%, respectively, of that of [3H]PK 11195. Displacement studies showed that unlabeled Ro 5-4864, diazepam, and flunitrazepam were much more potent in displacing [3H]PK 11195 from rat cerebral cortex and kidney membranes than from calf tissues. The potency of unlabeled Ro 5-4864 in displacing [3H]PK 11195 from the cerebral cortex of various other species was also tested, and the rank order of potency was rat = guinea pig greater than cat = dog greater than rabbit greater than calf. Analysis of these displacement curves revealed that Ro 5-4864 bound to two populations of binding sites from rat and calf kidney and from rat, guinea pig, rabbit, and calf cerebral cortex but to a single population of binding sites from cat and dog cerebral cortex. Using [3H]PK 11195 as a ligand, the rank order of binding capacity in cerebral cortex of various species was cat greater than calf greater than guinea pig greater than rabbit greater than dog greater than rat, whereas when [3H]Ro 5-4864 was used, the rank order of binding capacity was cat greater than guinea pig greater than rat greater than rabbit greater than calf greater than dog.

Animals↗
PubMed2004

PERIOD2::LUCIFERASE real-time reporting of circadian dynamics reveals persistent circadian oscillations in mouse peripheral tissues.

Mammalian circadian rhythms are regulated by the suprachiasmatic nucleus (SCN), and current dogma holds that the SCN is required for the expression of circadian rhythms in peripheral tissues. Using a PERIOD2::LUCIFERASE fusion protein as a real-time reporter of circadian dynamics in mice, we report that, contrary to previous work, peripheral tissues are capable of self-sustained circadian oscillations for >20 cycles in isolation. In addition, peripheral organs expressed tissue-specific differences in circadian period and phase. Surprisingly, lesions of the SCN in mPer2(Luciferase) knockin mice did not abolish circadian rhythms in peripheral tissues, but instead caused phase desynchrony among the tissues of individual animals and from animal to animal. These results demonstrate that peripheral tissues express self-sustained, rather than damped, circadian oscillations and suggest the existence of organ-specific synchronizers of circadian rhythms at the cell and tissue level.

Animals↗
PubMed2003

Temporal-spatial characterization of chicken clock genes: circadian expression in retina, pineal gland, and peripheral tissues.

The molecular core of the vertebrate circadian clock is a set of clock genes, whose products interact to control circadian changes in physiology. These clock genes are expressed in all tissues known to possess an endogenous self-sustaining clock, and many are also found in peripheral tissues. In the present study, the expression patterns of two clock genes, cBmal1 and cMOP4, were examined in the chicken, a useful model for analysis of the avian circadian system. In two tissues which contain endogenous clocks--the pineal gland and retina--circadian fluctuations of both cBmal1 and cMOP4 mRNAs were observed to be synchronous; highest levels occurred at Zeitgeber time 12. Expression of these genes is also rhythmic in several peripheral tissues; however, the phases of these rhythms differ from those in the pineal gland and retina: in the liver the peaks of cMOP4 and cBmal1 mRNAs are delayed 4-8 h and in the heart they are advanced by 4 h, relative to those in the pineal gland and retina. These results provide the first temporal characterization of cBmal1 and cMOP4 mRNAs in avian tissues: their presence in avian peripheral tissues indicates they may influence temporal features of daily rhythms in biochemical, physiological, and behavioral functions at these sites.

ARNTL Transcription Factors↗
PubMed1983

The regional distribution of neurotensin-like immunoreactivity in central and peripheral tissues of the cat.

The regional distribution of neurotensin-like immunoreactivity (NTLI) was studied by radioimmunoassay in central and peripheral tissues of the cat. In the brain, NTLI showed a wide distribution with highest concentrations in the hypothalamus, the caudate/putamen and the nucleus accumbens. Only low levels of NTLI were measured in the spinal cord and there was no difference between dorsal and ventral horn. In the periphery, NTLI was present in high concentrations in the adrenal medulla and in lower amounts in the superior cervical and the ciliary ganglion. NTLI was present in both lobes of the pituitary gland and throughout the gastrointestinal tract with high concentrations in the ileum. All other peripheral tissues tested contained low but detectable amounts of NTLI. Gel chromatography on Sephadex G-25 was used in order to characterize the immunoreactive material; NTLI in tissue extracts from 3 central and 3 peripheral tissues co-eluted in a single peak at the position of synthetic neurotensin. NTLI is widely distributed throughout cat tissues and there are important differences from the distribution pattern in the rat, the only other species examined in detail to date.

Animals↗
PubMed2007

Brain-derived neurotrophic factor enhances glucose utilization in peripheral tissues of diabetic mice.

AIMS: Repetitive subcutaneous or intracerebroventricular administration of brain-derived neurotrophic factor (BDNF) ameliorates glucose metabolism and enhances energy expenditure in obese diabetic C57BL/KsJ-db/db mice. To explore the mechanism of action through which BDNF regulates glucose metabolism, we examined the effects of BDNF on glucose utilization and norepinephrine (NE) content in peripheral tissues of diabetic mice. METHODS: [(14)C]2-deoxyglucose ([(14)C]2-DG) uptake into peripheral tissues was analysed after intravenous injection of [(14)C]2-DG in db/db and normal C57BL/6 mice, and [(14)C]2-DG uptake and NE content in peripheral tissues were analysed after subcutaneous administration of BDNF (20 mg/kg) to male db/db and normal mice for 8 days. RESULTS: [(14)C]2-DG uptake in the diaphragm, heart, gastrocnemius, soleus and interscapular brown adipose tissue (BAT) of db/db mice was significantly lower than in normal mice. Repetitive administration of BDNF to db/db mice for 8 days enhanced [(14)C]2-DG uptake in the diaphragm, heart, soleus, BAT and liver. The NE content in heart, skeletal muscle, interscapular BAT and liver of db/db mice given BDNF was high compared with db/db mice given vehicle, whereas no significant change in NE content in peripheral tissues was observed in normal mice given BDNF and those given vehicle. BDNF did not affect [(14)C]2-DG uptake or NE content in the white adipose tissue of db/db mice. CONCLUSIONS: These data indicate that BDNF ameliorates glucose metabolism by enhancement of glucose utilization in muscle and BAT, with this effect caused by modulation of the central and peripheral nervous systems.

Adipose Tissue, Brown↗
PubMed1992

Dose-response relationship between lymph insulin and glucose uptake reveals enhanced insulin sensitivity of peripheral tissues.

To examine the role of transcapillary insulin transport to peripheral insulin sensitivity in vivo, we performed dose-response experiments in which both plasma and thoracic duct lymph insulin and glucose utilization (Rd) were measured in conscious dogs. Euglycemic clamps (n = 22) consisted of a 3-h activation period in which insulin was infused (rates: "physiological" 3.6, 5.4, 7.2 pmol.min-1.kg-1; "pharmacological" 108 pmol.min-1.kg-1), followed by a 3-h deactivation period. [14C]inulin was also infused as a diffusionary marker. Insulin sensitivity was estimated as the ED50. When based on plasma insulin, ED50 was 480 pM. However, when calculated from lymph (i.e., interstitial) insulin measurements, ED50 was 240 pM. Thus, interstitial insulin measurements reveal that insulin sensitivity of peripheral tissues is approximately twice that estimated from plasma insulin and is similar to sensitivity reported for suppression of hepatic glucose production. Furthermore, although [14C]inulin achieved equilibrium between plasma and lymph within 180 min, within the physiological range, steady state plasma insulin was higher than insulin in lymph (306 +/- 18, 474 +/- 42, and 780 +/- 60 pM vs. 180 +/- 18, 318 +/- 12, and 504 +/- 36 pM; P less than 0.0001); plasma insulin achieved steady state faster than lymph insulin (6 +/- 1, 6 +/- 2, and 11 +/- 3 min vs. 29 +/- 4, 16 +/- 6, and 44 +/- 8 min; P less than 0.01) and disappeared faster (5 +/- 2, 7 +/- 2, and 15 +/- 6 min vs. 37 +/- 8, 32 +/- 4, and 43 +/- 9 min; P less than 0.01). The time course of lymph insulin at each dose was similar to that of Rd, and at each dose, unlike plasma insulin, lymph insulin was strongly correlated with Rd (r = 0.93 or better). At pharmacological hyperinsulinemia (plasma 35232 +/- 5250 pM, lymph 27366 +/- 4380 pM), Rd rose faster than lymph insulin and disappeared more slowly than insulin. Thus, lymph insulin data indicate that the periphery is more sensitive to insulin than previously realized from estimates based solely on plasma hormone. Furthermore, lymph insulin is proportional to Rd within the physiological but not pharmacological range of insulin, indicating that transcapillary insulin transport is rate limiting for insulin action in this range. Finally, based on in vivo lymph (i.e., interstitial) insulin measurements, peripheral tissue is almost twice as sensitive to insulin than previously realized.

Animals↗
PubMed1995

Virgin alpha beta and gamma delta T cells recirculate extensively through peripheral tissues and skin during normal development of the fetal immune system.

Current models of T cell migration place severe restrictions on the recirculation of virgin T cells, condemning them to migrate exclusively via high endothelial venules in lymph nodes until they either die or acquire the capacity to migrate to skin and peripheral tissues as memory cells following stimulation with antigen. We have demonstrated in the sheep fetus (which is immunologically virgin until after birth) that virgin T cells and dendritic cells circulate through skin and peripheral tissues during fetal life in the same non-random manner as adult T cells but in much larger numbers than they do in adult animals. Our data also showed that T cells do not discriminate between peripheral tissues and skin or lymph nodes on the basis of virgin or memory CD45R phenotype, or CD2, CD58 or CD44 phenotype, and with the possible exception of CD11a/CD18, that it is not mandatory for lymphocytes to be activated to adhesion moleculehi status in order to home to fetal skin. Our results indicate that unique tissue-homing specificities for extra-lymphoid tissues can be imprinted on virgin T cells independent of foreign antigen. Virgin T cells have previously been thought to be denied access to peripheral tissues; however, the large-scale traffic of virgin T cells through extra-lymphoid tissues in the fetus reported here provides a mechanism whereby direct virgin T cell interactions with self-antigens expressed only on tissues outside the thymus can occur repeatedly during development of the fetal immune system.

Age Factors↗
PubMed1997

High affinity neurotensin receptor mRNA distribution in rat brain and peripheral tissues. Analysis by quantitative RT-PCR.

Neurotensin (NT) is widely distributed in the central nervous system (CNS) and peripheral tissues, and its actions are mediated by a specific family of G protein-coupled receptors. In this study, the authors have measured the levels of gene expression of the high-affinity neurotensin receptor (NTR) with quantitative reverse-transcriptase-polymerase chain reaction (RT-PCR). In the rat brain, the highest quantities of NTR mRNA were found in the ventral mesencephalon and in the hypothalamus. Surprisingly, almost identical quantities were detected in both structures, despite results from in situ hybridization studies revealing a low expression of NTR mRNA in the hypothalamus. The RT-PCR data suggest that large scale NTR mRNA synthesis is occurring in restrictive hypothalamic nuclei. Intermediate levels of expression were detected in the prefrontal cortex and striatum, and scant levels in the cerebellum. In peripheral tissues, the highest levels of NTR mRNA were detected in the colon, followed by the liver, and then duodenum and pancreas. In this study, the sensitivity and the accuracy of the quantitative RT-PCR method provided the means to estimate the relative distribution of NTR mRNA between brain structures and peripheral tissues. Therefore, this study promotes a better understanding of the localization of NTR synthesis in relationship with the various physiological effects of NT.

Animals↗
PubMed1999

Peripheral tissue distribution of orphanin FQ precusor mRNA in stroke-prone spontaneously hypertensive rats.

The heptadecapeptide orphanin FQ (OFQ) is a recently discovered neuropeptide that exhibits structural features reminiscent of the opioid peptides and that is an endogenous ligant to a G protein-coupled receptor sequentially related to the opioid receptors. OFQ was originally isolated from brain, but the presence of OFQ in peripheral tissues, especially in cardiovascular system, has not been clarified. The present study was designed to investigate the peripheral tissue distribution of OFQ precusor mRNA in stroke-prone spontaneously hypertensive rats (SHRSP) and compare the difference of OFQ precusor mRNA expression in aorta or cultured vascular smooth muscle cells (VSMCs) between SHRSP and wistar-Kyoto normotensive (WKY) rats. By using quantitative reverse transcription-polymerase chain reaction (RT-PCR), OFQ precusor mRNA was detected in aorta and ovary at high levels comparable with the amounts found in brain. Moderate expression was found in testis, while a little OFQ precusor mRNA could be detected in atrium. All other peripheral tissues examined from SHRSP, including ventricle, liver, lung and kidney, showed no expression of OFQ precusor mRNA. In the vascular system, OFQ precusor mRNA was expressed in aorta, pulmonary artery, renal artery and vein at high levels comparable with the amounts found in brain. We also found that OFQ precusor mRNA levels were much higher in aorta or cultured VSMCs from SHRSP than those from WKY rats. In conclusion, the present study has shown that OFQ precusor mRNA is present in some peripheral tissues, especially in cardiovascular and reproductive system, suggesting that OFQ possibly involves in the regulation of cardiovascular and reproductive functions.

Animals↗
PubMed1991

Regional distribution and partial molecular characterization of CD4-related mRNA in human brain and peripheral tissues.

We purified human poly(A)+ RNA from 11 individuals to assess the regional distribution of CD4 and CD4-related mRNA transcripts in human brain and in peripheral tissues by Northern blot hybridization. A 3.0 kb CD4 mRNA transcript was expressed in all brain areas and several peripheral tissues examined. A second CD4-related 1.8 kb mRNA species showed an uneven distribution in the brain with cortical regions possessing highest levels and basal ganglia, thalamus, cerebellum and spinal cord containing relatively lower amounts. Messenger RNA transcripts for CD8, a T cell specific marker, were not detectable in human brain by Northern analysis, yet were as abundant as CD4 in spleen. The expression of the 1.8 kb mRNA was tissue specific as it was not observed in peripheral tissues such as spleen, adrenal, colon, or lung, nor was it found in the choroid plexus, dorsal root ganglion and human neuronal (SY5Y) or astroglial (N132N1) cell lines. Blot hybridization and S1 nuclease protection analysis of poly(A)+ RNA with selective probes derived from CD4 indicated that the 1.8 kb mRNA transcript is truncated, lacking the extracellular protein coding region of CD4, and may in fact be a unique transcript from the CD4 gene locus rather than an alternatively spliced or processed CD4 mRNA.

Adult↗
PubMed1990

Distribution and localization of neurokinin A-like immunoreactivity and neurokinin B-like immunoreactivity in rat peripheral tissue.

Using specific radioimmunoassays and immunocytochemistry for neurokinin A (NKA) and neurokinin B (NKB), distribution and localization of these peptides in rat peripheral tissues were studied. NKA-like immunoreactivity (NKA-LI) was present in highest levels of 15.7-23.9 pmol/g wet wt. and NKB-like immunoreactivity (NKB-LI) was in levels of 0.33-0.67 pmol/g wet wt., throughout the gastrointestinal tract involving stomach, duodenum, jejunum, ileum and colon. Immunocytochemical analysis of gastrointestinal tract revealed that NKA-LI and NKB-LI localized in ganglia of both the submucosal and myenteric plexuses as well as varicose neurons in the mucosa and the muscle layer of the small and large intestine. On the other hand, high levels of NKB-LI were observed in oesophagus (0.83 +/- 0.08 pmol/g wet wt.), adrenal (1.02 +/- 0.21), head of pancreas (0.73 +/- 0.06) and kidney (0.98 +/- 0.05). The present study shows the difference of localization of NKA-LI and NKB-LI in peripheral tissues and suggests that NKB may have some physiological role differing from that of NKA in peripheral tissues.

Animals↗
PubMed2001

Novel method for localized, functional sympathetic nervous system denervation of peripheral tissue using guanethidine.

A simple technique for local chemical sympathectomy of peripheral tissues is described using guanethidine. Multiple microinjections of guanethidine were made into inguinal or epididymal white adipose tissue (IWAT and EWAT) pads or spleens of hamsters. Guanethidine virtually abolished the sympathetic innervation of both EWAT and IWAT, as measured by the absence of significant norepinephrine (NE) tissue content two weeks later and as suggested by the two-fold increase in IWAT mass characteristic of surgically induced WAT denervation. These measures were not affected in the contralateral pads given equivolumetric injections of saline. Guanethidine injections into the spleen lead to a functional sympathectomy, as indicated by significant depletions of NE content. Because guanethidine treatment did not decrease body mass, induce ptosis, or spread to closely associated adjacent tissue (contralateral EWAT pad), no chemical-induced malaise or global sympathetic denervation was suggested. Guanethidine was more effective than two other local sympathectomy treatments, injections of the sympathetic neurotoxin anti-dopamine-beta-hydroxylase saporin or surgical denervation, in decreasing IWAT NE content and increasing IWAT pad mass. Collectively, these results suggest that locally applied, chemical sympathectomy with guanethidine provides an effective, restricted method for sympathectomizing WAT, spleen and likely other peripheral tissues.

Adipose Tissue↗
PubMed1996

Immunological analysis of angiotensin AT2 receptors in peripheral tissues of neonatal and adult rats.

The peptide hormone angiotensin II (Ang II) is an important regulator of cardiovascular and body fluid homeostasis. Circulating Ang II mediates its physiological actions by activating Ang II receptors in both the periphery and the brain. Previous studies have demonstrated that Ang II receptor expression is high in neonates and decreases to adult levels as the animal matures. A greater proportion of this decline is due to reduced expression of the Type 2 (AT2) receptor subtype. In order to further investigate the expression of this receptor subtype, AT2-directed antisera were utilized to determine the expression of AT2 receptors in both neonatal and adult rat peripheral tissues by immunoblot analysis. The pattern of AT2 receptor immunoreactivity was largely consistent with previous studies employing autoradiographic and radioligand binding assays in peripheral tissues. However, AT2 receptor immunoreactivity was not seen in the adrenal, despite earlier reports of AT2 receptor expression in this peripheral tissue. These immunohistochemical studies also suggested that AT2 receptors undergo tissue-specific post-translational processing during development. Collectively, these results identify immunoreactive AT2 receptor populations in neonatal and adult rat peripheral tissues and further strengthen the hypothesis of AT2 receptor heterogeneity.

Adrenal Glands↗
PubMed1997

Tyrosine hydroxylase assay for detection of low levels of enzyme activity in peripheral tissues.

A nonisotopic assay for tyrosine hydroxylase, with optimized signal-to-noise ratios, enables determination of low levels of enzyme activity in peripheral tissues. DOPA produced by the enzyme is measured using HPLC with electrochemical detection. Increased signal-to-noise ratios are obtained by including in the reaction mixture glycerol for reduction of blank values and dihydropteridine reductase and NADPH for regeneration of the tetrahydropteridine cofactor. With this method, tyrosine hydroxylase activity can be detected in as few as 200 PC12 cells and in peripheral tissues at levels as low as 4.5 fmol/min/mg wet weight. The assay permits activity to be assessed in a variety of peripheral tissues.

Animals↗
PubMed2005

Expression of orexin receptors in the brain and peripheral tissues of the male sheep.

Orexins exert their effects through two specific receptors (OX1R and OX2R) that have been found mainly in the brain and also in peripheral tissues of rats and humans. Here, we demonstrate expression of mRNA encoding for ovine OX1R and OX2R in central and peripheral tissues of sheep. Gene expression for orexin receptors in the hypothalamus and the preoptic area was localised by in situ hybridisation. OX1R was detected in arcuate nuclei (ARC), median eminence (ME), the lateral hypothalamic nuclei and preoptic area (POA) and it was scattered along the third ventricle from the paraventricular (PVN) to the ventromedial hypothalamic nuclei (VMH). OX2R was localised in the PVN, ARC, ME, ventral VMH and a small region of the ventral POA. Gene expression for OX1R and OX2R in central and peripheral tissues was analysed using quantitative real time RT-PCR. Both orexin receptor genes were expressed in the hypothalamus, POA, hippocampus, amygdala, olfactory bulb, pineal gland and recess and pituitary gland, whereas only OX1R mRNA was detected in the testis, kidney and adrenal gland. The expression of the genes for orexin receptors in this range of ovine tissues suggests roles for orexins in multiple physiological functions, with actions at both central and peripheral levels.

Animals↗