Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0278080 (physical dependence)
 1,658 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It is frequently hypothesized that drug-induced alterations in the density of beta-adrenergic receptors underlie tolerance to and physical dependence on agonists and antagonists at beta-adrenergic receptors. Two approaches to determining the effect of treatment with drugs on the density of beta-adrenergic receptors are described. In the first, the density of beta-adrenergic receptors was measured on leukocytes taken from human subjects during and after drug treatment. Treatment with the antagonist propranolol caused an increase in the density of beta-adrenergic receptors on leukocytes, whereas treatment with the agonists terbutaline and ephedrine, or pindolol, an antagonist with intrinsic sympathomimetic activity, caused a decrease in the density of beta-adrenergic receptors. In the second approach, the effect of agonists on the density of beta-adrenergic receptors on C6 glioma cells in culture was determined. Incubation with the full agonist isoproterenol decreased the density of both beta 1- and beta 2-adrenergic receptors. In contrast, incubation with pindolol or celiprolol, also an antagonist with intrinsic sympathomimetic activity, selectively decreased the density of beta 2-adrenergic receptors. Pindolol and celiprolol may be useful in situations in which selective stimulation of beta 2-adrenergic receptors and blockade of beta 1-adrenergic receptors is desirable.
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PMID:Effects of chronic administration of agonists and antagonists on the density of beta-adrenergic receptors. 287 41

Ketamine is a dissociative anaesthetic that is being used in non-medical contexts. The effects of ketamine are very similar to those of phencyclidine, another dissociative anaesthetic that has enjoyed considerable popularity as a recreational drug. The effects of ketamine include analgesia, cardiovascular and respiratory stimulation, dissociation, hallucinations and anaesthesia. The potential dangers of uncontrolled ketamine use include psychosis and violence, accidents and marked psychomotor and cognitive impairment. Although studies have shown potential for tolerance to and physical dependence on ketamine, further investigation of these phenomena is needed. Ketamine is thought to produce most of its effects through antagonist activity at the PCP site of the NMDA receptor complex. Ketamine has sympathomimetic properties resulting from enhancement of catecholamine, and particularly dopamine, activity. While opioid receptor activity has been identified, this is relatively weak and the contribution to the effects of ketamine is not clear. Although much is known of the clinical uses and effects of ketamine, as yet little is understood of ketamine as a recreational drug and potential drug of dependence.
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PMID:Pharmacological properties of ketamine. 1620 65