Opiates antagonists

The effects of corticosteroids, cyclooxygenase blockers, leukotriene blockers, PAF antagonists, anti-TNF antibodies, oxygen radical scavengers, opiate antagonists, antihistamines, and calcium channel blockers in endotoxic shock were reviewed in 1990 (H17). In this section studies on this subject that have been published during the last few years are summarized. 

The abstinence syndrome, evoked in animals by the withdrawal of nicotine, appears to be similar to that seen following opiate withdrawal (Malin et al. 1992). Furthermore, Malin and co-workers have reported that the abstinence syndrome can be provoked by the administration of the opiate antagonist, naxolone, to nicotine-treated rats (Malin et al. 1993). These results suggest that the abstinence syndrome... 

Injection of the opiate antagonist naloxone precipitates the somatic signs of nicotine withdrawal (Adams and Cicero 1998 Carboni et al. 2000 Malin et al. 1993a), but not affective signs, such as intracranial self-stimulation (ICSS) threshold elevation (Watkins et al. 2000). Yet naloxone injection in a nicotine-infused rat is robustly aversive (Ise et al. 2000 Watkins et al. 2000). Therefore, the somatic signs may actually correspond better than ICSS thresholds to an aversive motivational state. 

The few controlled studies of pharmacotherapy for AN have largely been disappointing. No class of medication has consistently proved effective in the treatment of AN consequently, pharmacotherapy plays a relatively minor role in the routine management of the disorder. Nevertheless, a review of the medications tested for the treatment of AN is informative. Medications used in the treatment of AN include appetite stimulants, antidepressants, antipsychotics, anxiolytics, trace mineral supplementation, prokinetics, and opiate antagonists. 

In overdose, managing respiration is essential. Opiate antagonists may be used, but can provoke... 

Gillberg, C. (1995) Endogenous opioids and opiate antagonists in autism brief review of empirical findings and implications for clinicians. Dev Med Child Neurol 37 239-245. 

Miscellaneous compounds beto-blockers and opiate antagonists... 

The part played by endogenous opioid systems in the regulation of these various physiological and behavioral functions has led to the experimental application of opiate antagonists in psychiatric disorders. This chapter focuses on autism and self-injury, which are two potential indications for opiate antagonists in pediatric populations. In adults, treatment with opiate antagonists has shown to be useful in the relapse prevention of alcoholism as part of a comprehensive treatment approach (Anton et ah, 1999, 2001). 

There are two main hypotheses about the involvement of endogenous opioid systems in the maintenance of self-injurious behaviors (Sandman, 1988 Buitelaar, 1993). The pain hypothesis suggests that in some subjects self-injury does not induce pain because excessive basal activity of opioid systems in the CNS has led to an opioid analgesic state. The addiction hypothesis posits that particularly repetitive and stereotyped forms of self-injury stimulate the production and release of en-dogeneous opioids. Therefore, chronic maintenance of self-injury may be due to addiction to endogenous opioids or to positive reinforcement by a central release of opioids triggered by the self-injurious behavior. Irrespective of which hypothesis one favors, treatment with opiate antagonists seems to be a rational approach. 

In 1974, Liebeskind showed the existence of a central pain-suppressive system, and was able to produce analgesia by electrical stimulation of the periventricular gray matter within the brain. This electroanalgesia could be reversed by opiate antagonists, and showed a cross-tolerance with morphine-induced analgesia. These results indicated the existence of a neuronal system that uses an endogenous neuromodulator or neurotransmitter with opiate-like properties. 

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