Acute and Chronic Ethanol Consumption Effects on the Immunolabeling of Gq/11α Subunit Protein and Phospholipase C Isozymes in the Rat Brain

Abstract: The goal of this investigation was to examine whether postreceptor sites [G_q/11 protein and phospholipase C (PLC) isozymes] of the phosphoinositide signal transduction system are involved in neuroadaptational mechanisms in the brain during chronic ethanol consumption. It was observed that acute ethanol treatment has no effect on the immunolabeling of PLC-β₁, -γ₁, and -δ₁ and the α subunit of G_q/11 protein in the rat cortex as determined by western blotting using specific monoclonal antibodies. On the other hand, chronic ethanol consumption (15 days) resulted in a significant decrease in the immunolabeling of PLC-β₁, whereas under identical conditions, the immunolabeling of PLC-γ₁ and -δ₁ isozymes was not significantly altered. The decreased immunolabeling of PLC-β₁ during chronic ethanol consumption was not altered by 24 h of withdrawal after 15 days of ethanol consumption. The immunolabeling of the α subunit of G_q/11 protein was significantly decreased after 15 days of ethanol consumption but had returned to normal levels after 24 h of ethanol withdrawal. Also, chronic ethanol treatment resulted in a significant decrease in phosphatidylinositol 4,5-bisphosphate-specific PLC activity, which remained the same after 24 h of ethanol withdrawal. These results suggest that decreased PLC activity during ethanol consumption and its withdrawal may be due to decreased protein levels of the G_q/11 protein-coupled PLC-β₁ isozyme but not the PLC-γ₁ or -δ₁ isozyme in the rat cortex. It is possible that changes in the protein levels of the G_q/11 protein-coupled PLC-β₁ isozyme and in PLC activity in the brain may be involved in the cellular adaptation to chronic ethanol exposure.     

Imipramine-Induced Changes in 5-HT2 Receptor Sites and Inositoltrisphosphate Levels in Rat Brain

The effect of chronic administration of Imipramine on [³H]Spiperone binding to 5-HT₂ sites and inositoltrisphosphate (IP₃) levels in rat cerebral cortex was studied. Our data shows that treatment with imipramine (5 mg/kg body weight, intraperitoneally) for 30 days significantly down regulates 5-HT₂ receptors sites (262 ± 29 fmol/mg protein) in cerebral cortex (38%), compared to control rats (425 ± 60 fmol/mg protein., P < 0.001). However there was no significant change in the affinity of [³H]-Spiperone binding (kd) to 5-HT₂ sites in cerebral cortex after exposure to imipramine (Kd = 0.84 ± 0.11 nM). It is also observed that imipramine treatment significantly reduces 5-HT stimulated [³H]IP₃ formation in cerebral cortex (6,411 ± 708 dpm/mg protein), compared to the saline treated rats (12,238 ± 1,544 dpm/mg protein; P < 0.001), with concomitant decrease in Pdtlns-4–5-P₂. This study suggests that the therapeutic action of imipramine in brain might be by reducing hypersensitivity of 5-HT₂ receptors by down regulation, which leads to reduced levels of inositolphospholipids. This inturn reduces the levels of IP₃. In conclusion, imipramine acts at presynaptic site by blocking the reuptake of serotonin and at post synaptic site it downregulates 5-HT₂ sites with decreased IP₃ levels after chronic exposure.     

Polyamines and Somatic Embryogenesis in Carrot. III. Effects of Methylglyoxal bis(guanylhydrazone)

The effects of methylglyoxal bis(guanylhydrazone) (MGBG) onsomatic embryogenesis, titres of cellular polyamines and 1-aminocyclopropane-l-carboxylicacid, and the activity of arginine decarboxylase (ADC) werestudied using suspension cultures of carrot (Daucus carota L.).Whereas MGBG (0.1–0.5 mM) significantly inhibited thecellular levels of spermidine and spermine, putrescine levelswere higher in the treated tissue. MGBG also promoted ACC levelsin the cells. The activity of ADC was inhibited in the presenceof MGBG. Somatic embryogenesis in the auxin-free medium wascompletely inhibited by MGBG. The effects of MGBG on somaticembryogenesis were reversed by 0.1–0.2 mM spermidine butnot by spermine. These results are consistent with the suggestionthat an interaction between ethylene and polyamine bio-syntheticpathways through competition for the common precursor, S-adenosylmethionine,plays an important role in the development of somatic embryosin carrot cell cultures. ¹Scientific Contribution Number 1649 from the New HampshireAgricultural Experiment Station. This research was supportedby NSF Grant No. DCB-8615945, Central University Research Funds,UNH, and NHAES Project H-233 ²Present address: Nancy S. Papa, In Vitron Corporation, 4649LeBourget Drive, St. Louis, MO 63134, U.S.A. ³Present address: Dr. A. Jamal Khan, Department of Plant Science,College of Agriculture, Sultan Qaboos University, P.O. Box-32484,Al-Khod, Muscat, Sultanate of Oman (Received September 17, 1990; Accepted January 21, 1991)     

Isolation and nucleotide sequence of the hmp gene that encodes a haemoglobin-like protein in Escherichia coli K-12

Summary In the course of an attempt to identify genes that encode Escherichia coli dihydropteridine reductase (DHPR) activities, a chromosomal DNA fragment that directs synthesis of two soluble polypeptides of M_r 44000 and 46000 was isolated. These proteins were partially purified and were identified by determination of their N-terminal amino acid sequences. The larger was serine hydroxymethyltransferase, encoded by the glyA gene, while the smaller was the previously described product of an unnamed gene closely linked to glyA, and transcribed in the opposite direction. Soluble extracts of E. coli cells that overproduced the 44 kDa protein had elevated DHPR activity, and were yellow in colour. Their visible absorption spectra were indicative of a CO-binding b-type haemoprotein that is high-spin in the reduced state. The sequence of the N-terminal 139 residues of the protein, deduced from the complete nucleotide sequence of the gene, had extensive homology to almost all of Vitreoscilla haemoglobin. We conclude that E. coli produces a soluble haemoglobin-like protein, the product of the hmp gene (for haemoprotein). Although the protein has DHPR activity, it is distinct from the previously purified E. coli DHPR.     

Evaluation of antipyretic potential of Clitoria ternatea L. extract in rats.

The methanol extract of Clitoria ternatea L. root (MECTR) blue flowered variety (Family: Fabaceae), was evaluated for its anti-pyretic potential on normal body temperature and yeast-induced pyrexia in albino rats. Yeast suspension (10 ml/kg body wt.) increased rectal temperature after 19 hours of subcutaneous injection. The extract, at doses of 200, 300 and 400 mg/kg body wt., p.o., produced significant reduction in normal body temperature and yeast-provoked elevated temperature in a dose-dependent manner. The effect extended up to 5 hours after the drug administration. The anti-pyretic effect of the extract was comparable to that of paracetamol (150 mg/kg body wt., p.o.), a standard anti-pyretic agent.     

Impact of Routing Flexibility on the Performance of an FMS—A Simulation Study

The evolving manufacturing environment is characterized by a drive toward increasing flexibility. One possible manifestation of flexibility within an FMS is in the form of routing flexibility. Providing this typically is an expensive proposition, and system designers therefore aim to provide only the required levels commensurate with a given set of operating conditions. This paper presents a framework based on a Taguchi experimental design for studying the nature of the impact of varying levels of routing flexibility on the performance of an FMS. Simulation results indicate that increases in routing flexibility, when made available at the cost of an associated penalty on operation processing time, is not always beneficial. There is an optimal flexibility level, beyond which system performance deteriorates, as judged by the makespan measure of performance. It is suggested that the proposed methodology can be used in practice for not only setting priorities on specific design and control factors but also for highlighting likely factor level combinations that could yield near-optimal shop performance.     

The effect of chronic chlorpromazine administration on monoamine levels in various regions of rat brain

The neuroleptic drug, chlorpromazine (CPZ) has been shown to exert its antipsychotic effect by blocking post synaptic dopamine receptors. However, its effect on steady state levels of monoamines is still in discrepancy. In the present study, CPZ (4 mg/kg body weight) was administered intraperitoneally to adult Wistar rats chronically for 75 days and the levels of norepinephrine (NE), dopamine (DA) and 5-hydroxytryptamine (5-HT) were assayed in various brain regions by high performance liquid chromatography (HPLC). After the experimental period body and brain weights were not statistically different from controls. NE and 5-HT levels were increased only in hippocampus by 15% (p<0.01) and 16% (p<0.01) respectively. DA levels were consistently increased in cortex by 39% (p<0.001), striatum-accumbens by 18% (p<0.01), hippocampus by 27% (p<0.01), hypothalamus by 34% (p<0.001), cerebellum by 36% (p<0.001) and brainstem by 40% (p<0.001) in CPZ treated rats compared to controls. The results suggest that chronic CPZ administration increases DA levels in almost all regions of brain and reflect the ability of CPZ to preferentially interfere with synaptic transmission mediated by DA in brain. It also suggests that this increase in DA might be responsible for certain side effects seen in patients after chronic CPZ treatment.     

A Candidate Complex Approach to Study Functional Mitochondrial DNA Changes: Sequence Variation and Quaternary Structure Modeling of Drosophila simulans Cytochrome c Oxidase

A problem with studying evolutionary dynamics of mitochondrial (mt) DNA is that classical population genetic techniques cannot identify selected substitutions because of genetic hitchhiking. We circumvented this problem by employing a candidate complex approach to study sequence variation in cytochrome c oxidase (COX) genes within and among three distinct Drosophila simulans mtDNA haplogroups. First, we determined sequence variation in complete coding regions for all COX mtDNA and nuclear loci and their isoforms. Second, we constructed a quaternary structure model of D. simulans COX. Third, we predicted that six of nine amino acid changes in D. simulans mtDNA are likely to be functionally important. Of these seven, genetic crosses can experimentally determine the functional significance of three. Fourth, we identified two single amino acid changes and a deletion of two consecutive amino acids in nuclear encoded COX loci that are likely to influence cytochrome c oxidase activity. These data show that linking population genetics and quaternary structure modeling can lead to functional predictions of specific mtDNA amino acid mutations and validate the candidate complex approach. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.