Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Four schedules of subcutaneous morphine pellet implantation were developed to render rats rapidly physically dependent on morphine. The schedules included implantation of four morphine pellets over a 3-day period (schedule 1), six morphine pellets over a 3-day period (schedule 2), six pellets over a 7-day period (schedule 3), and ten pellets over a 10-day period (schedule 4). Each morphine pellet contained 75 mg of morphine base. The degree of morphine dependence was quantitated by determining the median effective dose (ED50) of naloxone required to induce the stereotyped jumping response. Hypothermia and weight loss, during abrupt and naloxone-induced withdrawal, were also measured. Rats on schedule 4 exhibited a high degree of dependence on morphine as evidenced by an extremely low naloxone ED50 for the precipitated withdrawal jumping response, whereas schedules 1 and 2 produced a low degree of dependence as shown by high naloxone ED50's. Further evidence for a high degree of physical dependence on morphine is schedule 4 rats was indicated by their greater loss in body weight and greater hypothermic response after abrupt and after naloxone precipitated withdrawal compared with these responsed in the rats in the other three schedules. A correlation was found to exist between naloxone ED50 for the jumping response, body weight loss, and hypothermia observed during naloxone-induced withdrawal in morphine-dependent rats. These studies suggest that the implantation of four morphine pellets in the rat produces a mild degree of dependence and that caution should be exercised when making generalized conclusions about the biochemical correlations involved when four or less number of pellets, each containing 75 mg of morphine base, are used to induce morphine dependence in the rat.
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PMID:Rapid induction and quantitation of morphine dependence in the rat by pellet implantation. 40 58

1. Tolerance to morphine-induced analgesia (hot plate and acetic acid whrithing test), hypothermia and lethality can be quantified in mice by measuring the degree of parallel shifts of semilog. dose-response relationships induced by repeated opioid administration. 2. A similar procedure can be used for the quantification of naloxone-induced withdrawal as an indicator of dependence. 3. The intensity of tolerance development with respect to time of administration and dosage of morphine varies with the test procedure. It is closely parallel, however, in both analgesic tests during acquisition of tolerance. 4. Log-log-linear relationships exist between tolerance in analgesic tests and physical dependence as determined by naloxone-induced withdrawal. 5. The minimum tolerance-inducing dose of morphine in different tests could not be correlated to the ED50's in these tests. 6. Chronic opiate treatment leads to a decrease or an increase in motility response to morphine, depending on the time that has elapsed after the last morphine administration.
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PMID:Quantitative assessment of tolerance to and dependence on morphine in mice. 55 28

The present experiments were performed to investigate the effects of the selective mu opioid receptor antagonist, beta-funaltrexamine (beta-FNA), on the physical dependence liability of butorphanol (a mixed agonist/antagonist opioid analgesic). Butorphanol (26 nmol/microliter/h) was continuously infused via osmotic minipumps into the lateral cerebral ventricle of male Sprague-Dawley rats for 72 h. beta-FNA (12, 24, and 48 nmol/5 microliter/rat) was administered ICV 3 h prior to and 48 h after initiation of the butorphanol infusion. Treatment with beta-FNA significantly diminished naloxone-induced escape behavior, hypothermia, and loss of body weight in a dose-dependent manner, while naloxone-induced teeth-chattering, forepaw tremors, and urination were also reduced, but in a dose-independent manner. These results suggest that the mu opioid receptor is partially involved in the development of physical dependence upon butorphanol.
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PMID:Effects of beta-funaltrexamine on butorphanol dependence. 152 43

The effects of morphine tolerance-dependence and abstinence on 5-HT1A receptors in brain regions and spinal cord of the rat were determined. Tolerance to and physical dependence on morphine was induced in male Sprague-Dawley rats by implanting six morphine pellets (each containing 75 mg of morphine free base) during a seven day period. Two groups of rats were used for binding studies. In one group the pellets were left intact (tolerant-dependent) and in the other they were removed (abstinent). Rats were killed, and spinal cords and brains were excised. Brain was dissected into seven regions (amygdala, hippocampus, hypothalamus, striatum, midbrain, pons + medulla and cortex). 5-HT1A receptors were characterized by using [3H]8-hydroxy-di-n-propylaminotetralin [( 3H]DPAT) as the ligand and unlabelled 5-HT to determine the non-specific binding. In morphine and placebo tolerant-dependent rats the binding of [3H]DPAT to 5-HT1A receptors in brain regions and spinal cord did not differ. The Bmax value of [3H]DPAT in the hypothalamus of morphine abstinent rats was decreased by 61.9%. No change in Bmax value was observed in other brain regions and spinal cord. The Kd values were unaffected. Subcutaneous administration of DPAT produced hypothermia in rats from which pellets had been removed. The intensity of DPAT-induced hypothermic response was greater in morphine abstinent rats as compared to placebo abstinent rats. Since DPAT is believed to have a major action on the presynaptic 5-HT neurons, it is concluded that in morphine abstinent rats 5-HT1A receptors are down-regulated in hypothalamus, but in morphine tolerant-dependent rats they are unaffected.
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PMID:Down-regulation of hypothalamic 5-HT1A receptors in morphine-abstinent rats. 214 90

The aim of the present study was to investigate if a physical dependence could be induced by chronic activation of the endogenous enkephalinergic system. We have therefore evaluated naloxone-induced withdrawal syndrome in rats after central infusion during 7 days of comparable antinociceptive doses of RB 38 A ((R,S)HONH-CO-CH2-CH(CH2C6H5)-CONH-CH(CH2C6H5)-COOH), a mixed enkephalin catabolism blocker and of the selective mu, DAGO (Tyr-D-Ala-Gly-(Me)Phe-Gly-ol) and delta, DSTBULET (Tyr-D-Ser(OtBu)-Gly-Phe-Leu-Thr), opioid agonists. The responses were compared to those induced by RB 38 B ((S,S)HONH-CO-CH2-CH(CH2C6H5)-CONH-CH(CH2C6H5)-COOH), a selective inhibitor of the 24.11 neutral endopeptidase (NEP) 'enkephalinase'. DAGO induced a severe withdrawal syndrome evidenced by a large weight loss, hypothermia, jumping, mastication, teeth chattering, diarrhoea, lacrimation and salivation. In contrast, DSTBULET and RB 38 A produced only a moderate physical dependence. Only two signs were statistically different in these two groups: wet dog shakes and temperature. Chronic i.c.v. administration of DAGO, DSTBULET and RB 38 A produced a time-dependent reduction in analgesia, but 120 h after continuous infusion only RB 38 A was able to still induce a significative antinociceptive effect. The present data suggest that even in the drastic conditions used here long-term complete inhibition of enkephalin catabolism induces a weak tolerance and a moderate physical dependence, similar to that produced by delta opioid agonists. This effect was not observed after chronic selective inhibition of NEP by RB 38 B.
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PMID:Differences in physical dependence induced by selective mu or delta opioid agonists and by endogenous enkephalins protected by peptidase inhibitors. 216 53

When given a two-bottle choice between gradually increasing morphine concentrations (in 0.2% saccharin) and plain tap water, C57BL/6J mice consumed almost 90% of their daily fluid intake from the morphine-saccharin bottle, while the DBA/2J strain, in contrast, consumed 13% or less from the morphine-saccharin solution. The C57BL/6J strain consistently consumed mean daily doses of morphine sulfate in excess of 200 mg/kg, which was sufficient to induce an easily discernable withdrawal syndrome upon removal of the morphine solution, either with or without naloxone challenge. Hypothermia, tremor, wet dog shakes, jumping, and diarrhea were prominent withdrawal signs. In separate experiments, the saccharin was removed from the morphine-containing bottle, yet the C57BL/6J mice continued to prefer the morphine solution over tap water. In complete contrast to the above, mice of the DBA/2J strain rejected the morphine-saccharin solution at the lowest concentration employed, and at no time did their mean daily morphine dose exceed 20 mg/kg. Thus, morphine-saccharin preference is strongly genetically determined, and a high degree of physical dependence can result in the morphine-preferring strain. Palatability differences appear not to be the predominant explanation for these differences in morphine-saccharin consumption.
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PMID:Physical dependence induced by the voluntary consumption of morphine in inbred mice. 232 Jun 38

The novel and highly selective, conformationally restricted enkephalin analogue for delta-opioid receptors, [D-Pen2,D-Pen5]enkephalin (DPDPE; Pen = penicillamine), was studied in various in vivo tests for analgesia, tolerance and physical dependence. Intracerebroventricular (i.c.v.) administration of DPDPE caused a dose-dependent, naloxone-reversible antinociception, measured with the heat-irradiant (tail-flick) method. Acute tolerance developed to the antinociceptive effect of DPDPE. DPDPE also caused mild signs of physical dependence (withdrawal hypothermia and body weight loss) after repeated peptide treatment. Severe signs of morphine withdrawal (e.g. withdrawal jumping) on the other hand, could not be reversed by the administration of DPDPE. It is concluded that the activation of central delta-opioid receptors may play a role in controlling pain mechanisms, and that this activation is followed by the rapid development of a tolerance to this action.
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PMID:Analgesic and tolerance-inducing effects of the highly selective delta opioid agonist [D-Pen2,D-Pen5]enkephalin in mice. 284 84

The establishment of, and sex differences in, physical dependence on methaqualone (MQ) in rats were studied by the drug-admixed food (DAF) method. Female and male rats were treated with MQ-admixed food on the same schedule of gradually increasing doses (0.5 and 1 to 6 mg of methaqualone/g of food). Only female rats showed hypothermia from MQ at 1 and 2 mg/g and motor incoordination from MQ at 4 and 6 mg/g of food. Moreover, after MQ withdrawal, severe withdrawal signs, including convulsions and death, were observed in female rats, but not in male rats. We also instituted a different schedule of graded increases in dose (1 and 2 to 10 and 12 mg/g of food) to develop physical dependence on MQ in male rats. Under this schedule male rats exhibited a hypothermia and severe motor incoordination from MQ 6 and 8 mg/g of food condition. After MQ withdrawal, various severe signs of MQ withdrawal occurred, including tremor, convulsions and death. These results demonstrate that severe physical dependence on MQ in both sexes can be established using the DAF method, and that there are marked sex differences in the physical dependence on MQ.
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PMID:Sex differences in physical dependence on methaqualone in the rat. 317 79

Using the technique of within-family selective breeding, we have generated mouse lines that differ genetically in sensitivity to the acute hypothermia induced by injection of 3 g/kg ethanol (EtOH). After 5 generations of selection, the difference in maximal hypothermic response between COLD and HOT lines was 1.6 degrees C in the first replicate and 1.2 degrees C in the second replicate. Estimates of realized heritability were h2 = .17 in each replicate. No differences in EtOH metabolism have developed, so the differences between HOT and COLD mice are presumably in neurosensitivity. These lines of animals should be useful for studying the biological mechanisms underlying neurosensitivity to EtOH. In conjunction with other selectively bred lines, they should improve our understanding of the genetic relationships among EtOH neurosensitivity, tolerance and physical dependence.
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PMID:Genetic selection of mouse lines sensitive (cold) and resistant (hot) to acute ethanol hypothermia. 382 97

The effects of clomipramine HCl (15 mg kg-1 i.p.) on behaviour, body temperature and brain amines were investigated in rats that had been chronically treated twice daily with increasing doses of delta 9-tetrahydrocannabinol (delta 9-THC, 2-6 mg kg-1 i.v.). delta 9-THC produced a biphasic change in behaviour, stimulation followed by depression, and a pronounced hypothermia. Tolerance developed rapidly to these effects of delta 9-THC. Chronic treatment with delta 9-THC reduced the levels of homovanillic acid, 5-hydroxytryptamine and noradrenaline. The level of dopamine was not altered with chronic treatment and tolerance appeared to develop to the increased levels of 5-hydroxyindoleacetic acid induced by delta 9-THC. Injection of clomipramine, 12-14 h after 2, 5 or 10 days of delta 9-THC treatment induced characteristic changes in the rats behaviour which consisted of writhes, backward kicking, wet shakes, jumps ataxia and front paw and whole body tremor. The severity of the behavioural changes appeared to be dependent on the period of delta 9-THC administration and they were not accompanied by a change in body temperature or consistent changes in brain amines or metabolites. The results indicate that physical dependence on delta 9-THC may occur since clomipramine is able to precipitate changes in behaviour, indicative on an abstinence syndrome, in rats chronically treated with delta 9-THC. It is suggested that tryptaminergic mechanisms are altered during chronic delta 9-THC treatment and that clomipramine induces the behavioural changes by interacting with an altered tryptaminergic system.
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PMID:Time-course of the effects of chronic delta 9-tetrahydrocannabinol on behaviour, body temperature, brain amines and withdrawal-like behaviour in the rat. 612 98


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