Effect of pentylenetetrazol treatment on cholecystokinin mRNA and peptide levels in rat hippocampus and cortex

After treatment with pentylenetetrazol (PTZ), cholecystokinin (CCK) mRNA and CCK-like immunoreactivity (CCK-LI) levels were determined in rat hippocampus and cortex at different time points. In the temporal cortex treatment with 60 mg/kg PTZ, i.p., induced increases of CCK mRNA and CCK-LI levels at 2 days after the injection. In the hippocampus, a similar increase of CCK mRNA level was observed on the second day. By contrast, in the frontal cortex, CCK-LI level was increased at 10 days after the treatment with PTZ. These data show that PTZ increases both CCK mRNA and CCK-LI levels in these rat brain regions at different time.     

Comparison of seizure related amino acid release in human epileptic hippocampus versus a chronic, kainate rat model of hippocampal epilepsy

Many ethical issues in emergency medicine involve the question of informed consent. In this article, the ethical basis for informed consent, the essential elements of a morally valid informed consent, and the inadequacy of the law as a moral guide for informed consent are discussed. The ways in which the nature of emergency medicine affects the application of moral principles are examined, and specific guidelines for assessing a patient's decision-making capacity regarding informed consent are provided.     

Effect of CCK-8 on audiogenic epileptic seizure in P77PMC rats

OBJECTIVE: We wished to ascertain whether different phenotypic appearances in patients with altered cellular sensitivity to thyroid hormones were related to the type of altered intra-cellular thyroid hormone effect. DESIGN: Blood samples were obtained from two members of a family suffering from generalized thyroid hormone resistance (GTHR) for hormone assays and examination of the cellular thyroid hormone effect, and the results compared with results from other families with signs of altered peripheral thyroid hormone sensitivity. PATIENTS: Two members of a family with thyroid hormone resistance and nine normal persons were studied. MEASUREMENTS: Basal thyroid hormone function tests were measured. The thyroid hormone effect on mononuclear blood cells was determined by measuring the thyroid hormone stimulated oxygen consumption and glucose uptake. RESULTS: The two family members appeared phenotypically normal except for nodular goitre. Thyroid hormone stimulated glucose uptake was depressed whereas thyroid hormone stimulated oxygen consumption was normal. CONCLUSION: Comparison of the present results of the cellular examination in two patients with GTHR, with the results obtained in other families with altered peripheral thyroid hormone sensitivity, suggest that the classic GTHR (phenotype: normal or with goitre) is linked to impaired thyroid hormone stimulated glucose uptake, whereas in patients with osteopetrosis, the thyroid hormone insensitivity seems located at the mitochondrial level (impaired thyroid hormone stimulated oxygen consumption.     

ANP gene expression in rat hearts during hypoxia

The relationships between muscle capillarization, estimated O2 diffusion distance from capillary to mitochondria, and O2 uptake (VO2) kinetics were studied in 11 young (mean age, 25.9 yr) and 9 old (mean age, 66.0 yr) adults. VO2 kinetics were determined by calculating the time constants (tau) for the phase 2 VO2 adjustment to and recovery from the average of 12 repeats of a 6-min, moderate-intensity plantar flexion exercise. Muscle capillarization was determined from cross sections of biopsy material taken from lateral gastrocnemius. Young and old groups had similar VO2 kinetics (tau VO2-on = 44 vs. 48 s; tau VO2-off = 33 vs. 44 s, for young and old, respectively), muscle capillarization, and estimated O2 diffusion distances. Muscle capillarization, expressed as capillary density or average number of capillary contacts per fiber/average fiber area, and the estimates of diffusion distance were significantly correlated to VO2-off kinetics in the young (r = -0.68 to -0.83; P < 0.05). We conclude that 1) capillarization and VO2 kinetics during exercise of a muscle group accustomed to everyday activity (e.g., walking) are well maintained in old individuals, and 2) in the young, recovery of VO2 after exercise is faster, with a greater capillary supply over a given muscle fiber area or shorter O2 diffusion distances.     

Presynaptic modulation of cholecystokinin release by protein kinase C in the rat hippocampus

The role of protein kinase C (PKC) in modulating the release of the octapeptide cholecystokinin (CCK-8) was investigated in rat hippocampal nerve terminals (synaptosomes). The PKC-activating phorbol ester 4beta-phorbol 12,13-dibutyrate (beta-PDBu) dose dependently (5-5,000 nM) increased CCK-8 release in a strictly Ca2+dependent way. This effect was observed only when synaptosomes were stimulated with the K+(A) channel blocker 4-aminopyridine (4-AP; 1 mM) but not with KCl (10-30 mM). The PDBu-induced exocytosis of CCK-8 was completely blocked by the two selective PKC inhibitors chelerythrine and calphostin-C and was not mimicked by alpha-PDBu, an inactive phorbol ester. In addition, an analogue of the endogenous PKC activator diacylglycerol, oleoylacetylglycerol, dose dependently increased CCK-8 exocytosis. Beta-PDBu (50-100 nM) also stimulated the 4-AP-evoked Ca2+-dependent release of the classic transmitter GABA, which co-localizes with CCK-8 in hippocampal interneurons. As a possible physiological trigger for PKC activation, the role of the metabotropic glutamate receptor was investigated. However, the broad receptor agonist (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid did not stimulate, but instead inhibited, both the CCK-8 and the GABA exocytosis. In conclusion, presynaptic PKC may stimulate exocytosis of distinct types of co-localizing neurotransmitters via modulation of presynaptic K+ channels in rat hippocampus.     

Effect of aging on gastrin receptor gene expression in rat stomach

Broiler chickens were raised in separate rooms kept at temperatures of either 27 C or 16 C from 28 through 39 days of age. At the high temperature mouth breathing was recorded, but it was absent at the lower temperature. The number of dust particles in the air was greater in the warm rooms. More than 50% of the chickens in warm rooms had microscopic lesions in the bronchi of their lungs, whereas fewer than 5% of chickens in cold rooms had such lesions. Large dust particles were visible in some of the lesions. It was postulated that the increased incidence of lung lesions in chickens from warm rooms was due to mouth breathing rather than the higher dust levels in the air of these rooms.     

Effects of felbamate, gabapentin and lamotrigine on seizure parameters and excitability in the rat hippocampus

The objective of this study was to compare the efficacy of nafarelin 200 micrograms (Group A), nafarelin 400 micrograms (Group B) and the combination of nafarelin 200 micrograms and norethisterone 1.2 mg (Group C) daily, in treating symptoms of endometriosis, American Fertility Society score and adverse events during 6 months of treatment. A prospective, randomized, double-blind parallel group study was performed in two centers and 49 women with endometriosis diagnosed laparoscopically were included. The patients were seen monthly for physical examination and records were taken for bleeding pattern, symptom score and adverse events. A control laparoscopy was performed at the end of 6 months of treatment. All patients were followed 6 months after treatment. At 3 and 6 months the pelvic examination total score had decreased significantly in all three groups. The total endometriosis score was significantly reduced in Groups B and C. After 2 months the total symptom score showed a significant decrease in Groups B and C. The frequency of hot flushes during the first month of treatment was lowest in Group C, but during the rest of treatment there were no differences between the groups. Best bleeding control was obtained in Group C. We conclude that nafarelin 200 micrograms daily has as good an effect on endometriosis symptoms as nafarelin 400 micrograms daily, and the addition of norethisterone 1.2 mg results in fewer hot flushes and better bleeding control.     

Autoradiographic localization of cholecystokinin (CCK) receptor expression during the development of azaserine-induced rat pancreatic carcinoma

The peptide hormone cholecystokinin (CCK) has been shown to stimulate the growth of azaserine-induced preneoplastic nodules in the rat pancreas. Previously, our labortory demonstrated by classical binding studies that CCK receptors are overexpressed in azaserine-induced rat pancreatic neoplasms. In the present study, we utilized autoradiography to determine the temporal course of this increased receptor binding. Male Lewis rats were given azaserine or saline injections and sacrificed at 2, 4, 8, 12, and 18 months of age. Pancreatic tissue was harvested and autoradiography using 125l-labeled. CCK-8 was performed. Densitometry measurements of azaserine-induced pancreatic nodules, internodular pancreas, and normal pancreatic tissue (from saline-treated controls) of each age group were taken with an image analyzer. There was no statistically significant difference in CCK binding to internodular pancreas and normal pancreas at any age. At 2 months of age, there was no significant increase in CCK binding to azaserine-induced pancreatic nodules. However, at 4, 8, 12, and 18 months of age there was significantly greater CCK binding to azaserine-induced pancreatic nodules than to both internodular pancreas and normal pancreas (p < 0.001 for all groups). At 18 months of age, one azaserine-treated animal developed a pancreatic acinar cell carcinoma, which likewise exhibited significantly greater CCK binding than internodular pancreas or normal pancreas (p < 0.001 for both). These findings demonstrate increased CCK binding in azaserine-induced preneoplastic pancreatic nodules and pancreatic acinar cell carcinoma, compatible with our previous demonstration of receptor overexpression in these tissues. Increased CCK binding first becomes apparent by 4 months following exposure to azaserine. These result suggest that overexpression of CCK receptors, located specifically on preneoplastic and neoplastic pancreatic lesions, results in increased CCK binding and is involved in the mediation of CCK-stimulated growth during azaserine-induced pancreatic carcinogenesis.     

Effects of chronic lithium and electroconvulsive stimuli on cholecystokinin mRNA expression in the rat brain

This study compares the effect of lithium (Li+) and electroconvulsive stimuli (ECS), two treatments commonly used in the treatment of affective disorders, on CCK mRNA expression in the rat brain. Two groups of rats receiving either 4 week Li+ or vehicle food supplementation and two groups receiving 6 ECS or 6 sham ECS during 2 weeks were studied. A significant decrease in CCK mRNA levels was seen in the caudate putamen both after Li+ as compared to vehicle and ECS as compared to sham ECS, 27 and 25%, respectively. A small (10%), yet significant, decrease was also seen in the inner entorhinal cortex after Li+. The results indicate that both Li+ and ECS inhibit CCK synthesis in the caudate putamen and are consistent with other findings of presumed decreased dopaminergic action in this part of the brain following these treatments.     

Effect of cholecystokinin on meal size and intermeal interval in the sham-feeding rat.

Gave 8 Sprague-Dawley male albino rats with gastric fistulas liquid food with the fistula closed (normal feeding) or open (sham feeding) after 3 hrs of food deprivation. Meal size (MS) was larger, latency to rest (LR) after a meal was longer, and intermeal interval (IMI) was shorter during sham feeding than during normal feeding. The putative satiety signal cholecystokinin (CCK, 20% pure) decreased MS and LR and increased IMI during sham feeding. After CCK (30 U/kg) the MS, LR, and IMI were the same during sham feeding as during normal feeding. The synthetic octapeptide (OCT) of CCK, which has the known biological actions of the complete hormone, reproduced the effects of CCK (30 U/kg) on MS and LR but not on IMI. The CCK and OCT were also tested for their ability to serve as a UCS for the formation of a conditioned taste aversion (CTA) in 10 3-hr food-deprived sham-feeding rats. The OCT did not serve as a UCS for a CTA in the same sham-feeding conditions in which OCT produced normal MS and LR. Impure CCK (30 U/kg), however, did serve as a UCS for a CTA under these conditions. Results are consistent with the hypothesis that CCK produces satiety in rats. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Early region-specific gene expression during tract formation in the embryonic rat forebrain

Expression profiles of two recently isolated cDNA fragments, M1 and M2, expressed in the medial telencephalon, were analyzed in developing rat forebrain by in situ hybridization histochemistry and correlative immunocytochemistry. M1 expression was observed in the most ventral portion of the hippocampal rudiment with a sharp dorsal boundary, from embryonic day (E) 12 onward. Its location corresponded to the fimbrial anlage. As the fimbria developed, segregated expression of M1 and neuron-specific class III beta-tubulin or GAP-43 became apparent, suggesting that part of the neuroepithelium producing fimbrial neuroglia expresses M1. M2 expression in the E12 telencephalon was confined to part of the medial cerebral wall, including the presumptive preoptic region and hippocampus, with a diffuse dorsal boundary. At the same stage, M2 expression also occurred in part of the dorsal diencephalon adjacent to the M2-positive telencephalic region, with caudal extension along the dorsal midline, and in the zona limitans intrathalamica. M2 expression domains lacked neuron-specific class III beta-tubulin immunoreactivity. During later stages, M2 expression was found in association with the corpus callosum, hippocampal commissure, fimbria, optic nerve, stria medullaris, tract of the zona limitans, and habenulopeduncular tract. In most cases, M2 expression was detected in regions corresponding to fiber tracts prior to arrival of the earliest axons, which could be detected by TAG-1- or GAP-43 immunohistochemistry. These findings suggest that specialized cell populations express M1 and/or M2 genes in paramedian regions of the forebrain in advance of developing axonal pathways and may be involved in early specification of tract location and differentiation of tract neuroglia.     

Effect of adrenal steroids on preproneurokinin-A gene expression in discrete regions of the rat brain

Glycogen phosphorylase b has been purified to homogeneity from the fat body of larval Manduca sexta. The purification procedure involved ammonium sulfate precipitation, and chromatography of DEAE-cellulose, 5'-AMP-Sepharose and Q-Sepharose. The final product, which showed a single band on SDS-PAGE with a M(r) = 92,500, was purified 50-fold from the original homogenate in a yield of about 3%. The molecular mass of the native purified phosphorylase b was estimated to be 186,000 Da from gel filtration, suggesting that the native enzyme is a dimer. The apparent Km values for glycogen, phosphate and 5'-AMP were 1.4 mM, 82 mM and 1.1 mM, respectively. The enzyme had a pH optimum of 7.05, and was inhibited by ATP, ADP and glucose, but not by trehalose, even at high concentration. Conversion of phosphorylase b into the a form was achieved by incubation with rabbit phosphorylase kinase and Mg(2+)-ATP. The molecular mass of phosphorylase a was estimated to be 250,000 Da by gel filtration chromatography. The specific activity of the a form in the presence of 5'-AMP was 1.6-1.7-fold higher than the specific activity of the b form under the same conditions. Thus, 5'-AMP activates the a form by about 20%, whereas ATP has no effect on the phosphorylase a activity.     

Differential regulation of GABA(A) receptor gene expression by ethanol in the rat hippocampus versus cerebral cortex

Previous research has shown that chronic ethanol consumption dramatically alters GABA(A) receptor alpha1 and alpha4 subunit gene expression in the cerebral cortex and GABA(A) receptor alpha1 and alpha6 subunit gene expression in the cerebellum. However, it is not yet known if chronic ethanol consumption produces similar alterations in GABA(A) receptor gene expression in other brain regions. One brain region of interest is the hippocampus because it has recently been shown that a subset of GABA(A) receptors in the hippocampus is responsive to pharmacologically relevant concentrations of ethanol. Therefore, we directly compared the effects of chronic ethanol consumption on GABA(A) receptor subunit gene expression in the hippocampus and cerebral cortex. Furthermore, we investigated whether the duration of ethanol consumption (14 or 40 days) would influence regulation of GABA(A) receptor gene expression in these two brain regions. Chronic ethanol consumption produced a significant increase in the level of GABA(A) receptor alpha4 subunit peptide in the hippocampus following 40 days but not 14 days. The relative expression of hippocampal GABA(A) receptor alpha1, alpha2, alpha3, beta(2/3), or gamma2 was not altered by either period of chronic ethanol exposure. In marked contrast, chronic ethanol consumption for 40 days significantly increased the relative expression of cerebral cortical GABA(A) receptor alpha4 subunits and significantly decreased the relative expression of cerebral cortical GABA(A) receptor alpha1 subunits. This finding is consistent with previous results following 14 days of chronic ethanol consumption. Hence, chronic ethanol consumption alters GABA(A) receptor gene expression in the hippocampus but in a different manner from that in either the cerebral cortex or the cerebellum. Furthermore, these alterations are dependent on the duration of ethanol exposure.     

Trimethyltin intoxication induces marked changes in neuropeptide expression in the rat hippocampus

Stenosis of vessels proximal to the renal artery is an unusual cause of allograft ischemia. We report four patients who had such 'suprarenal' arterial stenoses leading to graft dysfunction that was reversed with revascularization. We additionally review the existing literature on this entity, outline the etiologies of such stenoses, as well as discuss the surgical and non-surgical therapeutic options in patients with this uncommon cause of allograft dysfunction.     

Chymotrypsin gene expression in rat peripheral organs

Cdc25, the dual-specificity phosphatase that dephosphorylates the Cdc2-cyclin B complex at mitosis, is highly regulated during the cell cycle. In Xenopus egg extracts, Cdc25 is associated with two isoforms of the 14-3-3 protein. Cdc25 is complexed primarily with 14-3-3epsilon and to a lesser extent with 14-3-3zeta. The association of these 14-3-3 proteins with Cdc25 varies dramatically during the cell cycle: binding is high during interphase but virtually absent at mitosis. Interaction with 14-3-3 is mediated by phosphorylation of Xenopus Cdc25 at Ser-287, which resides in a consensus 14-3-3 binding site. Recombinant Cdc25 with a point mutation at this residue (Cdc25-S287A) is incapable of binding to 14-3-3. Addition of the Cdc25-S287A mutant to Xenopus egg extracts accelerates mitosis and overrides checkpoint-mediated arrests of mitotic entry due to the presence of unreplicated and damaged DNA. These findings indicate that 14-3-3 proteins act as negative regulators of Cdc25 in controlling the G2-M transition.     

Changing patterns of gene expression identify multiple steps during regression of rat prostate in vivo

The rat ventral prostate is an androgen-dependent organ that undergoes dramatic cell death upon removal of testosterone by surgical castration. Several well characterized criteria, such as nuclear condensation, organelle blebbing, and DNA fragmentation, have been used to demonstrate that most of this cell loss is due to programmed cell death, or apoptosis, of the secretory epithelial cells. In addition to changes in morphology, it is well known that cells undergoing apoptosis show alterations in gene expression, and it is widely assumed that many of these genes are directly involved in the mechanism of programmed cell death. Using poly A+ RNA derived from normal rat prostate as well as from the regressing prostates of castrated rats, we have used a PCR-based subtractive hybridization approach to generate complementary DNA (cDNA) libraries greatly enriched in cDNAs strongly regulated during rat prostate regression. Several hundred of the genes represented in these libraries appear to be strongly regulated during prostate regression and most of these are prostate specific. Sequence analysis indicates that up to 30% of these clones are similar or identical to genes of known function, approximately 20% are similar to expressed sequence tags (ESTs), and as many as 50% of these clones have not been characterized previously. Analysis of selected clones using in situ hybridization indicates that they are expressed specifically in prostate epithelial cells, and that certain of these clones are regulated temporally in a pattern consistent with apoptosis. The patterns of gene expression include: 1) genes whose expression decreases uniformly after removal of androgen, indicative of androgen sensitive genes; 2) genes whose expression increases in apoptotic prostate cells and in other tissues, suggesting a class of genes generally involved in apoptosis; 3) and genes whose expression increases in individual regressing prostate epithelial cells, suggesting a class of prostate specific genes associated with apoptosis.