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)

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 effects of serotonergic anxiolytics on the development of physical dependence on diazepam were examined in mice. Co-administration of buspirone (5-HT1A agonist) or ondansetron (5-HT3 antagonist), but not mianserin (5-HT1C antagonist) or ketanserin (5-HT2 antagonist) with diazepam potentiated the hypersensitivity to FG 7142 following chronic treatment with diazepam. This potentiation was not ascribable to pharmacokinetic interactions between diazepam and buspirone or ondansetron. These results suggest that co-administration of buspirone or ondansetron with diazepam may potentiate the development of physical dependence on diazepam; 5-HT1A and 5-HT3 receptors may be partially involved in the development of physical dependence on diazepam.
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PMID:Effects of serotonergic anxiolytics on physical dependence on diazepam in mice. 790 43

Anxiolytic-like activity in the mouse elevated plus-maze has recently been demonstrated for a range of compounds varying in degree of selectivity as 5-HT1A receptor antagonists. As tolerance and dependence liability are among the major clinical disadvantages of benzodiazepine therapy, the present study examined the effects of acute drug challenge on the plus-maze profiles of mice following daily treatment for 20 days with saline, chlordiazepoxide (CDP; 10.0 mg/kg) or the selective 5-HT1A receptor antagonist, WAY 100635 (0.1-1.0 mg/kg). To assess the development of physical dependence (withdrawal anxiogenesis), the study incorporated independent groups of animals tested on the maze 24 h after the final dose. Challenge with CDP or WAY 100635 produced behavioural changes indicative of anxiety reduction in mice that had received daily handling/saline for 20 days, thereby demonstrating that the chronic injection regimen per se had not compromised the acute efficacy of either agent. The absence of a similar response to acute drug challenge in mice treated chronically with CDP or WAY 100635 suggested the development of tolerance to the acute anxiolytic effects of both compounds under present test conditions. Despite these observations, however, no signs of enhanced anxiety were evident 24 h following discontinuation of chronic treatment with either compound. In a further experiment, the absence of withdrawal anxiogenesis at 24 h was replicated and extended to discontinuation periods of 36 and 48 h for both drugs. Although present results show that tolerance develops to the acute anxiolytic effects of CDP and WAY 100635 in the murine plus-maze, they also suggest that enhanced anxiety is not an inevitable consequence of abrupt cessation of chronic treatment with either compound.
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PMID:Tolerance to acute anxiolysis but no withdrawal anxiogenesis in mice treated chronically with 5-HT1A receptor antagonist, WAY 100635. 988 17

This review discusses efforts to develop rodent models for the study of neurobiological mechanisms underlying chronic alcohol drinking, alcoholism, and abnormal alcohol-seeking behavior. Selective breeding has produced stable lines of rats that reliably exhibit high and (for comparison purposes) low voluntary alcohol consumption. In addition, animal models of chronic ethanol self-administration have been developed in rodents, who do not have a genetic predisposition for high alcohol-seeking behavior, to explore environmental influences in ethanol drinking and the effects of physical dependence on alcohol self-administration. The selectively bred high-preference animals reliably self-administer ethanol by free-choice drinking and operantly respond for oral ethanol in amounts that produce pharmacologically meaningful blood alcohol concentrations (50 to 200 mg% and higher). In addition, the alcohol-preferring rats will self-administer ethanol by intragastric infusion. With chronic free-choice drinking, the high alcohol-preferring rats develop tolerance to the high-dose effects of ethanol and show signs of physical dependence after the withdrawal of alcohol. Compared with nonpreferring animals, the alcohol-preferring rats are less sensitive to the sedative-hypnotic effects of ethanol and develop tolerance more quickly to high-dose ethanol. Nonselected common stock rats can be trained to chronically self-administer ethanol following its initial presentation in a palatable sucrose or saccharin solution, and the gradual replacement of the sucrose or saccharin with ethanol (the sucrose/saccharin-fade technique). Moreover, rats that are trained in this manner and then made dependent by ethanol-vapor inhalation or liquid diet increase their ethanol self-administration during the withdrawal period. Both the selectively bred rats and common-stock rats demonstrate "relapse" and an alcohol deprivation effect following 2 or more weeks of abstinence. Systemic administration of agents that (1) increase synaptic levels of serotonin (5-HT) or dopamine (DA); (2) activate 5-HT1A, 5-HT2, D2, D3, or GABA(A) receptors; or (3) block opioid and 5-HT3 receptors decrease ethanol intake in most animal models. Neurochemical, neuroanatomical, and neuropharmacological studies indicate innate differences exist between the high alcohol-consuming and low alcohol-consuming rodents in various CNS limbic structures. In addition, reduced mesolimbic DA and 5-HT function have been observed during alcohol withdrawal in common stock rats. Depending on the animal model under study, abnormalities in the mesolimbic dopamine pathway, and/or the serotonin, opioid, and GABA systems that regulate this pathway may underlie vulnerability to the abnormal alcohol-seeking behavior in the genetic animal models.
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PMID:Animal models of alcoholism: neurobiology of high alcohol-drinking behavior in rodents. 1034 15

A variety of agents are currently used to treat the different anxiety disorders. Benzodiazepines, such as diazepam, are still preferred by some for the treatment of acute anxiety, with the advantage of a rapid onset of action, but they are less suitable for long-term treatment due to their potential for memory disturbances, sleepiness, lethargy, physical dependence and withdrawal. Compounds acting on monoamine neurotransmission are more suitable in the treatment of long-term or chronic anxiety disorders. Tricyclic antidepressants, such as imipramine, and monoamine oxidase inhibitors have been shown to be effective anxiolytics, but their side effects and safety concerns have limited their use. The probable role of disturbed serotonergic neurotransmission in anxiety is widely accepted and is the theoretical basis for the use of serotonergic agents such as the 5-HT1A receptor partial agonist, buspirone, and the selective serotonin reuptake inhibitors (SSRI), such as sertraline and paroxetine, which have largely replaced the earlier antidepressants. There is clear evidence for decreased serotonergic function in anxiety as well as in depression. Studies of patients with anxiety disorders show reduced levels of serotonin in cerebrospinal fluid (CSF) as well as reduced serotonin transporter binding. The role of noradrenaline in the control of anxiety is less well understood, although there is considerable evidence to suggest that a disturbance of noradrenergic neurotransmission may also contribute to the symptoms of anxiety. Noradrenaline modulates the activity of brain regions such as the amygdala which are associated with anxiety. In addition, anxiety states are associated with increases in the metabolite of noradrenaline, 3-methoxy-4-hydrophenylglycol (MHPG), and hypersecretion of noradrenaline in plasma and CSF. It appears likely that modulation of both serotonin and noradrenaline systems by dual-reuptake inhibitors may prove to be an advantage in the treatment of anxiety disorders. The serotonin-noradrenaline reuptake inhibitors (SNRI), venlafaxine, milnacipran and duloxetine are efficacious in relieving anxiety symptoms within depression, and some have proven efficacy in certain anxiety disorders. Initial studies suggest that dual acting agents may have an advantage over selective reuptake inhibitors in certain anxiety disorders, such as post-traumatic stress disorder (PTSD), and in patients with comorbid anxiety and depression.
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PMID:Serotonin noradrenaline reuptake inhibitors: A new generation of treatment for anxiety disorders. 2492 77