Opioid interaction

Propofol is primarily a hypnotic drug with substantial cardiorespiratory depressant actions and with no ability to produce neuromuscular blockade. While propofol lacks analgesic properties, its use permits lower doses of opioids. Likewise, less propofol is required for adequate hypnosis when it is administered with opioids. Thus, it is said that propofol and opioids interact synergistically. 

Opioids is the common name for all compounds which have the same mode of action as the constituents of opium, the dried milky liquid of the poppy seed, Papaver somniferum (Brownstein, 1993). All opioids interact in biological systems with the same type of receptor, the so-called opioid receptor. 

THC has a variety of pharmacologic effects that resemble those of amphetamines, LSD, alcohol, sedatives, atropine, and morphine. Important opioid interactions include reduction in opioid dependence in CB1 knockout mice lacking the CB1 receptor. 

Opioids interact with monoamine oxidase inhibitors, causing CNS excitation and hypertension (72). 

Megarbane B, Gueye P, Baud F. Interactions entre benzodiazepines et produits opioides. [Interactions between benzodiazepines and opioids.] Ann Med Interne (Paris) 2003 154(Spec No 2) S64-72. 

The availability of receptor knockout animals has also helped to illustrate cannabinoid-opioid interactions. CBi receptor knockout mice had greatly reduced morphine self-administration behavior and less severe naloxone-induced withdrawal signs than wild type animals, although the antinociceptive actions of morphine were unaffected in the knockout animals (40). The rimona-bant-precipitated withdrawal syndrome in THC-treated mice was significantly attenuated in animals with knockout of the pro-enkephalin gene (48). Knockout of the p opioid (OP3) receptor also reduced rimonabant-induced withdrawal signs in THC-treated mice, and there was an attenuated naloxone withdrawal syndrome in morphine-dependent CBi knockout mice (49,50). 

There are three main types of opioid receptor OP3 (p), OP2 (k), and OPi (5) receptors. They are mainly found within the central nervous system but also in the periphery. Subtypes of each have been identified. Opioids interact with these receptors to produce their effects, primarily by exerting presynaptic inhibition, which results in reduced release of excitatory transmitters. It is thought that analgesia is primarily mediated via activation of OP3... 

Stevenson GW, Folk JE, Linsenmayer DC, Kenner C, Rice KC, Negus SS (2003) Opioid Interactions in Rhesus Monkeys Effects of S + ii and S + K Agonists on Schedule-Controlled Responding and Thermal Nociception. J Pharm Exp Ther-ap 307 1054-1064... 

Opioids interact specifically with opioid receptors that are present throughout the body but are of primary importance within the CNS. Opioid drugs are used widely in both human and veterinary medicine as adjuncts to anesthesia and post-operatively because of their efficacy as analgesics and their relative safety even in critically ill or compromised patients. However, there are significant species differences in the pharmacological response to opioid administration and their use in the horse has been limited by undesirable physiological and behavioral side-effects and equivocal or short duration of analgesic efficacy (Bennett Steffey 2002). 

Morphine is the prototype for the class of natural and synthetic opioid analgesics and its toxicity stems mainly from its extensive effect on the central nervous system (CNS), principally that of a descending depression. Opioids interact with stereospecific and saturable binding sites mostly located in the CNS. Interaction with the opioid receptors mimics the actions of endogenous enkephalins and endorphins. Morphine is a pure opiate agonist and exerts its activity primarily on the mu receptor. Activity also appears to involve an alteration in the release of neurotransmitters, such as the inhibition of acetylcholine, norepinepherine, and dopamine. These actions result in the therapeutic effects of analgesia, sedation, euphoria, and decreased gastrointestinal motility however, in toxic amounts they can lead to... 

Furthermore, the substitution of methyl groups at the T and 6 position of Tyr (Dmt) yielded Dmt-Tic- peptides (3) endowed with dramatically increased 8-affinity, comparable to the 8-affinity observed with deltorphins [59-63]. On the other hand, p-affinity of 3 rose 20-fold relative to 1 and 2, while k-affinity increased over 40-fold in guinea pig brain membranes, 20-fold in rat brain synaptosomes compared to 2 and approximately 40-fold for both membrane preparation relative to 1. Inclusion of the Tyr-D-Ala-Phe message domain (4) essentially eliminated opioid interaction with k-receptors, whereas 8- and p-affinities were only moderately altered in comparison to DYN (1-11) -NH2 (Table... 

Vuyk J. Clinical interpretation of pharmacokinetic and pharmacod3mamic propofol-opioid interactions. Acta Anaesthesiol Belg (2001) 52, 445-51. 

Opioids interact with specific transmembrane G protein-coupled binding sites termed opiate or opioid receptors. These receptors are located primarily in spinal... 

Consequently, we undertook a study of morphine (both in the basic (M) and N-protonated forms (MH)), heroin (H) and cocaine (C) (protonated species), with particular emphasis on the cocaine-opioid interactions. Raman spectra of both the free samples and the C H and C M (1 1, w w) mixtures (with morphine either in the unprotonated or N-protonated forms) were obtained and analyzed in the light of the results obtained from quantum mechanical calculations, in view of understanding those interactions at a molecular level. 

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