Home About us Contact
|
Home About us Contact | ||
|
|
||
Physical Dependence (physical + dependence)
Selected AbstractsAlcohol-Induced Tolerance and Physical Dependence in Mice With Ethanol Insensitive ,1 GABAA ReceptorsALCOHOLISM, Issue 2 2009David F. Werner Background:, Although many people consume alcohol (ethanol), it remains unknown why some become addicted. Elucidating the molecular mechanisms of tolerance and physical dependence (withdrawal) may provide insight into alcohol addiction. While the exact molecular mechanisms of ethanol action are unclear, ,-aminobutyric acid type A receptors (GABAA -Rs) have been extensively implicated in ethanol action. The ,1 GABAA -R subunit is associated with tolerance and physical dependence, but its exact role remains unknown. In this report, we tested the hypothesis that ,1-GABAA -Rs mediate in part these effects of ethanol. Methods:, Ethanol-induced behavioral responses related to tolerance and physical dependence were investigated in knockin (KI) mice that have ethanol-insensitive ,1 GABAA -Rs and wildtype (WT) controls. Acute functional tolerance (AFT) was assessed using the stationary dowel and loss of righting reflex (LORR) assays. Chronic tolerance was assessed on the LORR, fixed speed rotarod, hypothermia, and radiant tail-flick assays following 10 consecutive days of ethanol exposure. Withdrawal-related hyperexcitability was assessed by handling-induced convulsions following 3 cycles of ethanol vapor exposure/withdrawal. Immunoblots were used to assess ,1 protein levels. Results:, Compared with controls, KI mice displayed decreased AFT and chronic tolerance to ethanol-induced motor ataxia, and also displayed heightened ethanol-withdrawal hyperexcitability. No differences between WT and KI mice were seen in other ethanol-induced behavioral measures. Following chronic exposure to ethanol, control mice displayed reductions in ,1 protein levels, but KIs did not. Conclusions:, We conclude that ,1-GABAA -Rs play a role in tolerance to ethanol-induced motor ataxia and withdrawal-related hyperexcitability. However, other aspects of behavioral tolerance and physical dependence do not rely on ,1-containing GABAA -Rs. [source] Preclinical abuse potential assessment of the anticonvulsant zonisamideDRUG DEVELOPMENT RESEARCH, Issue 2 2001Jenny L. Wiley Abstract Zonisamide (Zonegran®) is a broad-spectrum antiepileptic agent that shares some pharmacological properties with other anticonvulsants, including phenytoin, carbamazepine, and valproic acid, but is differentiated from these agents by the ability to significantly block T-type calcium channels. Zonisamide interacts with the ,-amino-butyric acid (GABA) receptor in an allosteric manner, and thus does not modulate GABA receptor effects. However, given the potential of drugs within the latter class for drug abuse in humans, an evaluation of zonisamide for abuse potential is an important component of its potential side-effect profile. In the present study, zonisamide was tested in animal models of the subjective and reinforcing effects of central nervous system (CNS) depressant drugs, e.g., diazepam discrimination in rats and intravenous self-administration in rhesus monkeys, respectively. In addition, zonisamide was evaluated for physical dependence liability in a chronic infusion model using rats. Zonisamide did not substitute for diazepam in rats trained to discriminate 2.5-mg/kg diazepam from vehicle nor was it self-administered by rhesus monkeys experienced in methohexital-reinforced responding. Continuous infusion of zonisamide (400 or 600 mg/kg/day) did not prevent the loss of body weight associated with discontinued pentobarbital infusion. These doses of zonisamide did produce some incomplete attenuation of observable signs of pentobarbital withdrawal, likely due to direct sedative or depressant effects of these high doses. These results suggest that zonisamide would not produce diazepam-like intoxication in humans nor would it likely be subject to abuse when made more widely available. Further, when administered chronically, zonisamide would not be expected to produce physical dependence of the CNS depressant type. Taken together, these results support the prediction that zonisamide would have low abuse liability. Drug Dev. Res. 54:66,74, 2001. © 2001 Wiley-Liss, Inc. [source] Molecular analyses and identification of promising candidate genes for loci on mouse chromosome 1 affecting alcohol physical dependence and associated withdrawalGENES, BRAIN AND BEHAVIOR, Issue 5 2008D. L. Denmark We recently mapped quantitative trait loci (QTLs) with large effects on predisposition to physical dependence and associated withdrawal severity following chronic and acute alcohol exposure (Alcdp1/Alcw1) to a 1.1-Mb interval of mouse chromosome 1 syntenic with human chromosome 1q23.2-23.3. Here, we provide a detailed analysis of the genes within this interval and show that it contains 40 coding genes, 17 of which show validated genotype-dependent transcript expression and/or non-synonymous coding sequence variation that may underlie the influence of Alcdp1/Alcw1 on ethanol dependence and associated withdrawal. These high priority candidates are involved in diverse cellular functions including intracellular trafficking, oxidative homeostasis, mitochondrial respiration, and extracellular matrix dynamics, and indicate both established and novel aspects of the neurobiological response to ethanol. This work represents a substantial advancement toward identification of the gene(s) that underlies the phenotypic effects of Alcdp1/Alcw1. Additionally, a multitude of QTLs for a variety of complex traits, including diverse behavioral responses to ethanol, have been mapped in the vicinity of Alcdp1/Alcw1, and as many as four QTLs on human chromosome 1q have been implicated in human mapping studies for alcoholism and associated endophenotypes. Thus, our results will be primary to further efforts to identify genes involved in a wide variety of behavioral responses to alcohol and may directly facilitate progress in human alcoholism genetics. [source] Does Dihydrohonokiol, a Potent Anxiolytic Compound, Result in the Development of Benzodiazepine-like Side Effects?JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 8 2000HISASHI KURIBARA The aims of this study were to assess whether dihydrohonokiol, 3,-(2-propenyl)-5-propyl-(1,1,-biphenyl)-2,4,-diol (DHH-B), a potent anxiolytic compound, developed benzodiazepine-like side effects. A 1 mgkg,1 dose of diazepam, almost equivalent to the minimum dose for the anxiolytic effect, disrupted the traction performance, potentiated hexobarbital-induced sleeping and impaired learning and memory performance. DHH-B, even at a dose of 1 mg kg,1 (i.e. five times higher than the minimum dose for significant anxiolytic effect) neither developed diazepam-like side effects nor enhanced the side effects of diazepam. Rather, the potentiation by diazepam of hexobarbital-induced sleeping was reduced by 1 mg kg,1 DHH-B. Furthermore, mice treated with 10 daily administrations of 1 and 5 mg kg,1 diazepam, but not 0.2,5 mg kg,1 DHH-B, showed precipitated withdrawal symptoms characterized by hyper-reactivity, tremor and tail-flick reaction when they were challenged with flumazenil (10 mg kg,1 i.p.). These results suggest that, unlike the benzodiazepine anxiolytic diazepam, DHH-B is less likely to induce motor dysfunction, central depression, amnesia or physical dependence at the effective dose required for the anxiolytic effect. [source] Revisiting Intragastric Ethanol Intubation as a Dependence Induction Method for Studies of Ethanol Reward and Motivation in RatsALCOHOLISM, Issue 3 2010Simone Braconi Background:, The purpose of this study was to re-examine intragastric ethanol intubation as a dependence induction method that effectively induces physical dependence upon ethanol over a short time period, is devoid of intrinsic stress artifacts, inexpensive, and easy to implement. Methods:, Male Wistar rats were subjected to ethanol dependence induction via intragastric ethanol intubation. Ethanol solution (final concentration 20%, made up in a dietary liquid vehicle consisting of powdered milk, sucrose, and water) was intubated 4 times per day, at 4-hour intervals, for 6 consecutive days (for a total of 10 g/kg/day). The utility of this procedure was evaluated for inducing physical dependence, determined by daily and final withdrawal ratings. Anxiety-like behavior associated with ethanol dependence history was examined using the elevated plus-maze (EPM) test, conducted 5 days after ethanol withdrawal. To evaluate whether potential stress-like effects of intragastric intubation per se produce lasting effects on behavior, experimentally naive rats were compared with vehicle-intubated rats for anxiety-like behavior on the EPM. Results:, Blood alcohol levels reached stable levels between 200 and 250 mg%, measured 1 hour after the second and third ethanol intubation on days 2, 4, and 6. Ethanol-treated rats developed significant somatic withdrawal signs, recorded daily between 10 and 12 hours after the last ethanol administration. At 5 days postwithdrawal, ethanol-treated rats showed significant anxiety-like behavior, measured by decreased open arm time and open arm entries on the EPM, compared with vehicle controls. Additionally, ethanol postdependent rats showed decreased open arm time compared with experimentally naive rats. EPM performance did not differ between vehicle-intubated and naive rats. No withdrawal seizures were observed and mortality rate was near zero. Conclusions:, These findings suggest that intragastric ethanol administration produces a behavioral profile consistent with ethanol dependence (i.e., significant withdrawal signs after termination of ethanol exposure and elevated anxiety-like behavior persisting beyond completion of physical withdrawal), and that the intubation procedure itself does not produce lasting nonspecific anxiety-like effects. Thus, under the conditions employed here, this procedure provides an effective tool for inducing and evaluating the consequences of ethanol dependence in animal models of ethanol reward and motivation. [source] Alcohol-Induced Tolerance and Physical Dependence in Mice With Ethanol Insensitive ,1 GABAA ReceptorsALCOHOLISM, Issue 2 2009David F. Werner Background:, Although many people consume alcohol (ethanol), it remains unknown why some become addicted. Elucidating the molecular mechanisms of tolerance and physical dependence (withdrawal) may provide insight into alcohol addiction. While the exact molecular mechanisms of ethanol action are unclear, ,-aminobutyric acid type A receptors (GABAA -Rs) have been extensively implicated in ethanol action. The ,1 GABAA -R subunit is associated with tolerance and physical dependence, but its exact role remains unknown. In this report, we tested the hypothesis that ,1-GABAA -Rs mediate in part these effects of ethanol. Methods:, Ethanol-induced behavioral responses related to tolerance and physical dependence were investigated in knockin (KI) mice that have ethanol-insensitive ,1 GABAA -Rs and wildtype (WT) controls. Acute functional tolerance (AFT) was assessed using the stationary dowel and loss of righting reflex (LORR) assays. Chronic tolerance was assessed on the LORR, fixed speed rotarod, hypothermia, and radiant tail-flick assays following 10 consecutive days of ethanol exposure. Withdrawal-related hyperexcitability was assessed by handling-induced convulsions following 3 cycles of ethanol vapor exposure/withdrawal. Immunoblots were used to assess ,1 protein levels. Results:, Compared with controls, KI mice displayed decreased AFT and chronic tolerance to ethanol-induced motor ataxia, and also displayed heightened ethanol-withdrawal hyperexcitability. No differences between WT and KI mice were seen in other ethanol-induced behavioral measures. Following chronic exposure to ethanol, control mice displayed reductions in ,1 protein levels, but KIs did not. Conclusions:, We conclude that ,1-GABAA -Rs play a role in tolerance to ethanol-induced motor ataxia and withdrawal-related hyperexcitability. However, other aspects of behavioral tolerance and physical dependence do not rely on ,1-containing GABAA -Rs. [source] Tramadol versus Buprenorphine for the Management of Acute Heroin Withdrawal: A Retrospective Matched Cohort Controlled StudyTHE AMERICAN JOURNAL ON ADDICTIONS, Issue 2 2006Threlkeld Threlkeld MD Many medications have been used over the past thirty years for the treatment of opioid withdrawal, including propoxyphene, methadone, clonidine, parenteral buprenorphine, and, more recently, sublingual buprenorphine. Each has been found to have clinical strengths and limitations. Tramadol is a centrally acting synthetic analgesic with opiate activity primarily due to the binding ofa metabolite to the , receptor. Despite this , receptor activity, tramadol appears to have low abuse potential and is a non-scheduled analgesic. The pharmacologic profile of tramadol makes it a candidate for opiate withdrawal treatment. A chart review was undertaken to retrospectively compare treatment outcomes of heroin-dependent patients when detoxified with parenteral buprenorphine (1996,1997) versus tramadol (1999,2000). Inclusion criteria for this study were heroin as drug of choice, current opioid physical dependence (ie, withdrawal symptoms), no current abuse of oral opioid analgesics, and no alcohol or benzodiazepine withdrawal symptoms. Patient cases that met inclusion criteria were group-matched between buprenorphine and tramadol on the basis of age, sex, and amount of heroin used (bags/ day). Charts were audited for patient demographics, daily heroin use at admission, withdrawal symptoms, and discharge status. In total, 129 patient charts were reviewed, and 115 met all inclusion criteria and were group-matched (45 patients in the buprenorphine group, seventy in the tramadol group). There were no differences in demographics between the two groups of patients. Fifty-six percent of the buprenorphine group and 71% of the tramadol group completed detoxification; tramadol-treated patients had significantly higher average withdrawal symptoms when compared to the buprenorphine group and a greater reduction in withdrawal symptoms over time. Finally, the number of side effects was small and did not differ between the groups. The results of this study are consistent with previous pilot reports that indicated few clinical differences between parenteral buprenorphine and oral tramadol protocols when used in the management of acute heroin withdrawal. As a consequence, tramadol shows some promise as an opioid withdrawal management medication. [source] How to design an opioid drug that causes reduced tolerance and dependenceANNALS OF NEUROLOGY, Issue 5 2010Amy Chang Berger BS Mu opioid receptor (MOR) agonists such as morphine are extremely effective treatments for acute pain. In the setting of chronic pain, however, their long-term utility is limited by the development of tolerance and physical dependence. Drug companies have tried to overcome these problems by simply "dialing up" signal transduction at the receptor, designing more potent and efficacious agonists and more long-lasting formulations. Neither of these strategies has proven to be successful, however, because the net amount of signal transduction, particularly over extended periods of drug use, is a product of much more than the pharmacokinetic properties of potency, efficacy, half-life, and bioavailability, the mainstays of traditional pharmaceutical screening. Both the quantity and quality of signal transduction are influenced by many regulated processes, including receptor desensitization, trafficking, and oligomerization. Importantly, the efficiency with which an agonist first stimulates signal transduction is not necessarily related to the efficiency with which it stimulates these other processes. Here we describe recent findings that suggest MOR agonists with diminished propensity to cause tolerance and dependence can be identified by screening drugs for the ability to induce MOR desensitization, endocytosis, and recycling. We also discuss preliminary evidence that heteromers of the delta opioid receptor and the MOR are pronociceptive, and that drugs that spare such heteromers may also induce reduced tolerance. ANN NEUROL 2010;67:559,569 [source] Clonidine Attenuates Naloxone-Induced Opioid-Withdrawal Syndrome in Cholestatic Mice,,BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 3 2001Ahmad Reza Dehpour Naloxone-precipitated withdrawal syndrome has been described in a mouse model of acute cholestasis. Thus we aimed at determining whether central noradrenergic hyperactivity is involved in manifestation of naloxone-precipitated withdrawal syndrome in mice with obstructive cholestasis. Acute cholestasis was induced by bile duct resection in mice and physical dependence was observed by precipitating a withdrawal syndrome with naloxone (2 mg/kg, intraperitoneally) 5 days after induction of cholestasis. Administration of clonidine (0.1 mg/kg, intraperitoneally), an ,2 -adrenoceptor agonist, 15 min. before naloxone injection significantly alleviates withdrawal severity in cholestatic mice. However, pretreatment of animals with yohimbine (3 mg/kg, intraperitoneally), an ,2 -adrenoceptor antagonist, 15 min. before clonidine blocked this ameliorative effect of clonidine. The results of this study support the evidence for involvement of the ,2 -adrenoceptors in the withdrawal syndrome of cholestasis in a mouse model. [source] Spinal administration of lipoxygenase inhibitors suppresses behavioural and neurochemical manifestations of naloxone-precipitated opioid withdrawalBRITISH JOURNAL OF PHARMACOLOGY, Issue 2 2003Tuan Trang This study investigated the role of spinal lipoxygenase (LOX) products in the induction and expression of opioid physical dependence using behavioural assessment of withdrawal and immunostaining for CGRP and Fos protein expression in the spinal cord. Administration of escalating doses (5,50 mg kg,1; i.p.) of morphine for 5 days markedly elevated CGRP-like immunoreactivity in the dorsal horn of the rat spinal cord. Naloxone (2 mg kg,1; i.p.) challenge precipitated a robust withdrawal syndrome that depleted CGRP-like immunoreactivity and increased the number of Fos-like immunoreactive neurons in the dorsal horn. Intrathecal administration of NDGA (10, 20 ,g), a nonselective LOX inhibitor, AA-861 (1.5, 3 ,g), a 5-LOX selective inhibitor, or baicalein (1.4, 2.8 ,g), a 12-LOX selective inhibitor, concurrently with systemic morphine for 5 days or as a single injection immediately preceding naloxone challenge, blocked the depletion of CGRP-like immunoreactivity, prevented increase in the number of Fos-like immunoreactive neurons in the dorsal horn, and significantly attenuated the morphine withdrawal syndrome. The results of this study suggest that activity of LOX products, at the spinal level, contributes to the expression of opioid physical dependence, and that this activity may be expressed through increased sensory neuropeptide release. British Journal of Pharmacology (2003) 140, 295,304. doi:10.1038/sj.bjp.0705440 [source] Behavioural and biochemical evidence for interactions between ,9-tetrahydrocannabinol and nicotineBRITISH JOURNAL OF PHARMACOLOGY, Issue 2 2002Emmanuel Valjent Behavioural and pharmacological effects of ,9-tetrahydrocannabinol (THC) and nicotine are well known. However, the possible interactions between these two drugs of abuse remain unclear in spite of the current association of cannabis and tobacco in humans. The present study was designed to analyse the consequences of nicotine administration on THC-induced acute behavioural and biochemical responses, tolerance and physical dependence. Nicotine strongly facilitated hypothermia, antinociception and hypolocomotion induced by the acute administration of THC. Furthermore, the co-administration of sub-threshold doses of THC and nicotine produced an anxiolytic-like response in the light,dark box and in the open-field test as well as a significant conditioned place preference. Animals co-treated with nicotine and THC displayed an attenuation in THC tolerance and an enhancement in the somatic expression of cannabinoid antagonist-precipitated THC withdrawal. THC and nicotine administration induced c-Fos expression in several brain structures. Co-administration of both compounds enhanced c-Fos expression in the shell of the nucleus accumbens, central and basolateral nucleus of the amygdala, dorso-lateral bed nucleus of the stria terminalis, cingular and piriform cortex, and paraventricular nucleus of the hypothalamus. These results clearly demonstrate the existence of a functional interaction between THC and nicotine. The facilitation of THC-induced acute pharmacological and biochemical responses, tolerance and physical dependence by nicotine could play an important role in the development of addictive processes. British Journal of Pharmacology (2002) 135, 564,578; doi:10.1038/sj.bjp.0704479 [source] Quality of life in stroke patientsACTA NEUROLOGICA SCANDINAVICA, Issue 5 2003K. Jaracz Objectives , To describe global and domain-specific quality of life (QOL) after stroke and to identify the factors that are important for post-stroke QOL. Material and methods , A hospital-based sample of 72 stroke patients was followed up for 6 months after stroke onset. QOL was assessed using the Polish version of the Quality of Life Index. Regression analysis was performed to identify the variables that best predicted QOL. Results , The overall QOL of stroke patients was relatively good, although worse than that of subjects in a comparison group. The highest QOL was found in the ,Family' domain, and the lowest in the ,Health and functioning' domain. Emotional support, depression and functional disability were three separate variables explaining 38% of the variance in QOL. Conclusions , Strengthening of family support, treatment of depression and reduction of physical dependence may be the decisive factors in improving post-stroke QOL. [source] Post-stroke quality of life and depressionACTA NEUROPSYCHIATRICA, Issue 5 2002Krystyna Jaracz Background: Studies on the determinants of the quality of life (QOL) after stroke bring differing results depending on the applied concept of QOL. This may lead to confusion about the contribution of various factors to the post-stroke QOL. Objective: The aim of the study was: (i) to investigate functional and psychological QOL in the individuals after the first ischemic stroke; (ii) to identify the most important correlates of QOL; and (iii) to examine the significance of depression among the other possible predictors of QOL. Methods: A hospital-based sample of 72 stroke patients was followed up to 6 months after stroke onset. QOL was assessed using the Polish version of the Quality of Life Index and the Sickness Impact Profile. A multiple regression procedure was performed to examine relationships between QOL and the study variables. Results: In spite of good recovery, the psychological and functional QOL of the examined patients was impaired, although the negative impact of stroke was greater on the objective QOL than on the subjective QOL. Stroke-related impairment, depression, functional disability and marital status predicted 80% of the variance in the functional QOL. Emotional support, depression and functional disability explained 38% of the variance in psychological well-being. Conclusions: Depression and physical disability were the most important predictors of QOL after stroke since their impact on QOL was more robust in comparison to the remaining variables. For improving QOL, a comprehensive care for patients aimed at reducing physical dependence and ameliorating depressive symptoms could be recommended. [source] Molecular basis of opioid dependence: role of signal regulation by G-proteinsCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2003Prudence H Tso Summary 1.,Morphine and opiate narcotics are potent analgesics that have a high propensity to induce tolerance and physical dependence following their repeated administration. 2.,The molecular basis of opiate dependence has not been completely elucidated, although the participation of opioid receptors is a prerequisite. Cellular dependence on opioids is believed to result from the chronic stimulation of opioid-regulated signalling networks. 3.,As G-protein-coupled receptors, the opioid receptors must rely on heterotrimeric G-proteins for signal transduction. Recent advances in our understanding of G-protein signalling have unveiled novel signalling molecules and mechanisms, some of which may be intricately involved in the manifestation of opiate dependence. 4.,In the present review, we will attempt to trace chronic opioid signals along elaborate G-protein-regulated pathways. [source] | ||||||||||||||||||||||