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Opiate Agonist (opiate + agonist)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Ultra-rapid opiate detoxification: from clinical applications to basic science

ADDICTION BIOLOGY, Issue 2 2003
EMMANUEL STREEL
Rapid or ultra-rapid opiate detoxification has become increasingly popular in both private and public addiction centres. These techniques seem to facilitate the transfer of opiate-dependent patients from opiate agonist to opiate antagonist. Despite the probable complex neuropharmacological aspects involved in these procedures, their development over nearly three decades is notable for the almost complete absence of clinically relevant animal studies. This paper discusses the historical background of this occurrence, and reviews the small number of animal studies that have been conducted. Many discussions and arguments about the techniques seem to underscore their true purpose, which is not "simply to detoxify" opiate-addicted patients but to initiate long-term management with naltrexone. For this reason, it may be better to conceptualize these techniques not as "rapid detoxification" but as "rapid antagonist induction". [source]

Neural Circuits Regulating Pulsatile Luteinizing Hormone Release in the Female Guinea-Pig: Opioid, Adrenergic and Serotonergic Interactions

JOURNAL OF NEUROENDOCRINOLOGY, Issue 3 2001
A. C. Gore
Abstract We studied three neurotransmitters involved in the regulation of pulsatile luteinizing hormone (LH) release: opioid peptides, serotonin and norepinephrine, using the ovariectomized guinea-pig. This is an attractive animal model due to the regularity of its LH pulses, enabling any disruptions to be clearly ascertained. In all experiments, a specific agonist or antagonist was administered, either alone or serially to enable detection of interactions, and effects on mean LH concentrations, pulse amplitude and interpulse interval were determined by PULSAR analysis. In the ovariectomized guinea-pig, catecholamines are stimulatory (acting through the ,1 and ,2 but not , receptors, unlike other species), opioids inhibitory and serotonin permissively stimulatory to pulsatile LH release. Stimulatory effects of the opiate antagonist were not blocked by pretreatment with an ,1 - or ,2 -adrenergic antagonist. Similarly, pretreatment with the opiate antagonist did not prevent the suppression of LH release by ,1 and ,2 antagonists. This suggests that, in the guinea-pig, effects of opiates and catecholamines on LH release are exerted by independent pathways to luteinizing hormone releasing hormone (LHRH) neurones. For the opiate,serotonin interactions, pretreatment with the serotonergic antagonist did not block the stimulatory effect of the opiate antagonist on LH release. However, pretreatment with the opiate agonist could not be overcome by the serotonergic agonist. This suggests that the effects of the serotonin system on LHRH release may be indirectly mediated by opioid neurones. Taken together, these studies demonstrate that the three neurotransmitter systems studied are critically involved in normal pulsatile LH release in the female guinea-pig, and demonstrate novel functional relationships between the opioid and the adrenergic and serotonergic systems. [source]

Effect of Naloxone on Appetitive and Consummatory Phases of Ethanol Self-Administration

ALCOHOLISM, Issue 7 2001
Amanda L. Sharpe
Background : The opioid system has been implicated in ethanol self-administration. Morphine, an opiate agonist, can sometimes increase the amount of ethanol consumed, and opiate antagonists such as naloxone and naltrexone decrease the amount of ethanol consumed in both animals and humans. The objective of this study was to examine the effect of naloxone on appetitive (or seeking) and consummatory behaviors by using an operant model developed to separate these two phases of self-administration. Methods: Intraperitoneal injections of naloxone (0.3,10 mg/kg) or vehicle were given before operant self-administration sessions to assess the effect on lever pressing (appetitive behavior) and subsequent consumption. Effects were measured in two groups of rats: one self-administered a 3% sucrose solution and the other a 10% ethanol solution. Results: Naloxone dose-dependently decreased ethanol and sucrose consumption by an earlier cessation of drinking in the session compared with vehicle injection days. There were some effects on appetitive responding after treatment with naloxone, but none was statistically significant. Conclusions: Naloxone may decrease ethanol self-administration by decreasing the postingestive or pharmacological effects of alcohol. This model provides a new method for examining the effects of potential pharmacotherapeutics on alcohol self-administration behavior. [source]

Options in Prehospital analgesia

EMERGENCY MEDICINE AUSTRALASIA, Issue 1 2002
Meredith L Borland
Abstract Background: Prehospital analgesia options for paramedics have been limited due to the difficulty in achieving safe and effective pain relief without compromising transportation to hospital. The present paper identifies the analgesia methods currently available in the prehospital setting so as to evaluate the various options and highlight areas for future research. Methods: A literature review of Medline and Embase databases from 1966 until the present was undertaken. Further hand searching of all the references identified in these papers was also performed. All current literature was analysed and categorized according to one of four levels of evidence using National Health and Medical Research Council of Australia guidelines (1999). Results: There is a paucity of randomized control trials relating to prehospital analgesia. All published literature was level III or IV prospective or retrospective studies. Drug options used included nitrous oxide/oxygen mixtures, intravenous/intramuscular nalbuphine, intravenous tramadol and intravenous pure opiate agonists. Conclusions: The evidence supporting analgesic options in the prehospital setting is limited. There are few published data in this area despite the inadequacy of pain relief being recognized as a weakness in prehospital care. Prehospital analgesia is an area worthy of innovative methods for the administration of safe and effective analgesics without significant impact on transport times. Such methods should be prospectively evaluated in well-constructed trials. [source]

Clinical diagnosis and treatment of suspected neuropathic pain in three dogs

AUSTRALIAN VETERINARY JOURNAL, Issue 1-2 2009
RG Cashmore
Three dogs were referred to The Queen's Veterinary School Hospital at University of Cambridge for chronic behavioural or locomotor disorders associated with pain. All three had been unsuccessfully treated with conventional analgesics, including non-steroidal anti-inflammatory drugs, glucocorticoids and opiate agonists, prior to referral, with minimal or no response. They were investigated by neurological examination plus conventional ancillary diagnostic tests and therapeutic drug trials. Ruling out other causes of pain and applying previously well-described criteria, each case was diagnosed as consistent with neuropathic pain, a poorly recognised condition in domestic dogs. Treatment with the tricyclic antidepressant drug, amitriptyline, or the antiepileptic drug, gabapentin, resulted in either a dramatic improvement or full resolution of clinical signs in all cases. [source]