Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026837 (muscle rigidity)
 1,077 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of the present study was to investigate physical dependence upon diazepam systematically in two inbred strains of rats, Lewis (LEW) and Fischer 344 (F344). Rats were chronically fed food containing diazepam on an escalating drug dosage schedule, from 1 and 2 to 12 mg/g of food, over a period of 30 days. During treatment, the growth curve in LEW and F344 rats was suppressed compared with the respective controls. Motor incoordination was evaluated by a rotarod performance test. The ranking of the motor incoordination during the final concentration of diazepam was as follows: F344 greater than LEW. After substitution of normal food for the diazepam-admixed food, various signs of diazepam withdrawal occurred 16-120 h later. These signs included vocalization, irritability, muscle rigidity, ear-twitching, Straub's tail, piloerection, fascicular twitch, tremor, convulsion, and death. The incidences of vocalization, ear-twitching, piloerection, and tremor in F344 were significantly higher than those in LEW rats. Furthermore, two of six F344 rats showed spontaneous convulsions and one rat died of convulsions. Overall withdrawal scores were significantly greater in F344 (16.0) than in LEW (6.3) rats. These results suggest that diazepam withdrawal severity is strongly influenced by genetic factors, and F344 rats are highly susceptible to dependence upon benzodiazepines.
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PMID:Genetic differences in the development of physical dependence upon diazepam in Lewis and Fischer 344 inbred rat strains. 143 78

Sex differences in physical dependence on barbital (BAR), which is not readily metabolized in rats, were studied by the drug-admixed food method. The concentration of BAR in the food was gradually increased from 1 and 2 up to 6 and 8 mg/g food concurrently available to each rat over a period of 36 days in both male and female Sprague-Dawley rats. Sedation and muscle relaxation were observed in males at the 4 and 6 mg/g condition and to a greater degree at 6 and 8 mg/g of food. This effect was seen only at the highest drug concentration, 6 and 8 mg/g food, in females. Physical dependence was assessed in both sexes after substitution of normal food for the BAR-admixed food. Various signs of BAR withdrawal were observed including vocalization, irritability, muscle rigidity, tremors and convulsions. The incidence of convulsions was 76.9% in females and 45.5% in males, respectively. Maximum weight loss was 15.4% in females and 12.1% in males. However, brain BAR concentrations in the male rats were higher than that in the female rats 9 hours before onset of withdrawal and at all later time points tested. Thus, we have demonstrated that weak sex differences in physical dependence on BAR exist and suggest that this difference resulted from a difference in CNS sensitivity to BAR.
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PMID:[Sex differences in the physical dependence on barbital in rats]. 382 11

Sex differences in physical dependence on sodium pentobarbital in the rat were studied by the drug-admixed food (DAF) method. With male rats, the concentration of pentobarbital in the food was gradually increased from 2 to 30 mg/g over a period of 50 days. The final level of drug intake was approximately 1.7 g/kg/day. At pentobarbital concentrations of 20 and 22 mg/g of food, sedation and mild muscle relaxation were observed. At the highest drug concentration, 30 mg/g of food, marked muscle relaxation was noted. With female rats, the concentration of pentobarbital in the food was gradually increased from 1 to 16 mg/g over a period of 47 days. The final level of intake was approximately 1.0 mg/kg/day. At drug concentrations of 12 and 14 mg/g, sedation and mild muscle relaxation appeared. At 16 mg/g, female rats showed marked muscle relaxation similar to that of the male rats. To produce severe loss of muscle tone, the male rats required twice as much pentobarbital as the female rats. After substitution of normal food for the pentobarbital-admixed food, various signs of pentobarbital withdrawal occurred in both sexes. These signs included vocalization, irritability, muscle rigidity, tremors and convulsions. Onset of withdrawal was more rapid in the females, and the maximum weight loss was greater, 8.0% compared to 3.8% in the males. Physical dependence on pentobarbital was easily developed in both sexes by the DAF method. There was a marked sex difference in withdrawal which we attribute to sex differences in drug metabolizing enzyme activity.
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PMID:Sex differences in the induction of physical dependence on pentobarbital in the rat. 409 88

We studied the involvement of beta-adrenoceptors in the physical dependence formation of barbital. 1. Propranolol (at a dose of 0.5 or 1.0 mg/g food) and barbital were applied simultaneously as a mixture with animal food (barbital-propranolol combination). Barbital was applied on a schedule of gradually increasing dosages from 0.5-and-1.0 to 6-and-8 mg/g food over 36 days. Only the animals dosed with barbital exhibited severe withdrawal signs such as spontaneous withdrawal convulsions. The animals dosed with propranolol alone showed no changes even on withdrawal of the drug. The formation of physical dependence on barbital was obviously inhibited by the combination of barbital and propranolol. 2. Cross-application of propranolol (30 and 60 mg/kg, p.o., and 10 and 30 mg/kg, i.p.) following withdrawal of barbital resulted in the inhibition of the spontaneous withdrawal convulsions, muscle rigidity and hyperirritability. It also inhibited significantly tranylcypromine-induced convulsions, while it failed to inhibit similarly induced hyperthermia. These results including previous findings of effects of monoamine-related compounds on barbital withdrawal convulsions suggest that the balance of activities of noradrenergic neurons, especially that of alpha- and beta- receptors, has great influence on both the formation of physical dependence on barbital and the manifestation of withdrawal convulsions.
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PMID:Effects of propranolol on barbital dependence formation and withdrawal signs. 668 67

Rats offered a nutritionally balanced and complete liquid diet containing 35% of energy as ethanol, 12% as fat, 21% as protein, and the balance as carbohydrate consumed greater than 9 g/kg ethanol after 10 days. Rats displayed signs of physical dependence and tolerance while showing a net gain in weight. Physical dependence was indicated by severe intensity of the following signs during withdrawal from ethanol: Muscle rigidity; tail tremors; caudal tremors; and general tremors. Severity of these signs reached a maximum intensity by 19 h after withdrawal of ethanol. Tolerance was exhibited by chronically treated rats as measured by significantly reduced time off the belt after 7 days. Concentrations of ethanol in blood were documented on selected mornings and were observed to increase. These data suggest that physical dependence and tolerance can be induced through voluntary consumption of ethanol by rats and without nutritional compromises or weight loss.
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PMID:Induction of physical dependence on and tolerance to ethanol in rats fed a new nutritionally complete and balanced liquid diet. 677 98

Medications which bind to opioid receptors are increasingly being prescribed for the treatment of multiple and diverse chronic painful conditions. Their use for acute pain or terminal pain is well accepted. Their role in the long-term treatment of chronic noncancer pain is, however, controversial for many reasons. One of the primary reasons is the well-known phenomenon of psychological addiction that can occur with the use of these medications. Abuse and diversion of these medications is a growing problem as the availability of these medications increases and this public health issue confounds their clinical utility. Also, the extent of their efficacy in the treatment of pain when utilized on a chronic basis has not been definitively proven. Lastly, the role of opioids in the treatment of chronic pain is also influenced by the fact that these potent analgesics are associated with a significant number of side effects and complications. It is these phenomena that are the focus of this review. Common side effects of opioid administration include sedation, dizziness, nausea, vomiting, constipation, physical dependence, tolerance, and respiratory depression. Physical dependence and addiction are clinical concerns that may prevent proper prescribing and in turn inadequate pain management. Less common side effects may include delayed gastric emptying, hyperalgesia, immunologic and hormonal dysfunction, muscle rigidity, and myoclonus. The most common side effects of opioid usage are constipation (which has a very high incidence) and nausea. These 2 side effects can be difficult to manage and frequently tolerance to them does not develop; this is especially true for constipation. They may be severe enough to require opioid discontinuation, and contribute to under-dosing and inadequate analgesia. Several clinical trials are underway to identify adjunct therapies that may mitigate these side effects. Switching opioids and/or routes of administration may also provide benefits for patients. Proper patient screening, education, and preemptive treatment of potential side effects may aid in maximizing effectiveness while reducing the severity of side effects and adverse events. Opioids can be considered broad spectrum analgesic agents, affecting a wide number of organ systems and influencing a large number of body functions.
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PMID:Opioid complications and side effects. 1844 35