Morphine antinociceptive action

Bhargava HN, Cao YJ. (1997). Effects of noribogaine on the development of tolerance to antinociceptive action of morphine in mice. Brain Res. 771(2) 343-46. 

Activities and sites of antinociceptive action of morphine-like analgesics, 6, 79... 

Borszcz, G. S. Differential contributions of medullary, thalamic, and amygdaloid serotonin to the antinociceptive action of morphine administered into the periaqueductal gray a model of morphine analgesia, Behav. Neurosci. 1999, 133, 612-631. 

Asano, T., Dohi, S., lida, H. Antinociceptive action of epidural KATP channel openers via interaction with morphine and an a2-adrenergic agonist in rats, Anesthesia and Analgesia 2000, 90, 1146-1151. 

Jhamandas, K.H., Sutak, M., Flenderson, G. Antinociceptive and morphine modulatory actions of spinal orphanin FQ, Can. J. Physiol. Pharmacol. 1998, 76, 314-324. 

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). 

The conformation of the morphine C-ring has a substantial bearing, both qualitatively and quantitatively, on the nature of a compound s opioid actions. The presence of a 5-Me substituent, in metopon (74), for example, afforded a modest increase in antinociceptive actions, without a parallel increase in unwanted responses. 

The antagonist potency of an opioid ligand is only rarely determined as a pA2 parameter more commonly the dose (e.g. AD50) that abolishes the antinociceptive action of a fixed amount of an agonist such as morphine or pethidine is measured and compared with that of a standard antagonist. In Janssen s procedure/21 fentanyl (the agonist) is injected sc into rats at the... 

Activities and sites of antinociceptive action of morphine-like analgesics. 6, 79 Adrenergic neurone blocking agents, 1, 161 Advances in penicillin research, 7, 1... 

A number of in vivo pharmacological studies reported that amino acid substitution in position 6 of 14-O-methyloxymorphone (48) afforded derivatives 55-60 that produce potent antinociceptive actions via peripheral mechanisms after s.c. administration in different pain models such as acute nociception i.e. tail-flick test [68], inflammatory pain i.e. formalin test [68] and carrageenan-induced hindpaw inflammation [75] and visceral pain i.e. acetic acid-induced writhing test [93]. In the tail-flick test in the rat, the 6-amino acid derivatives were 19- to 209-fold more potent than morphine (Table 7) and showed similar potency to fentanyl after s.c... 

Effect of some prostaglandin synthesis inhibitors on the antinociceptive action of morphine in albino rats Srivastava, D. N. Bhattacharya, S. K. Sanyal, A. K. 

The involvement of a cholinergic component in the mechanism of action of morphine was proposed even before acetylcholine (ACh) had been shown positively to be present in the central nervous system. Slaughter and Munsell [70] demonstrated that the antinociceptive action of morphine in the cat was potentiated by concurrent administration of neostigmine, an inhibitor of the enzyme cholinesterase, a Rnding later confirmed in man [71,72]. Since then, a number of investigations have attempted to implicate ACh in morphine analgesia [73]. 

Initial work with the /3-adrenoceptor antagonist, propranolol, showed an antagonistic action against the antinociceptive action [222] and other morphine-induced behaviour [223], but more recently other workers [221] concluded that neither propranolol nor practolol affected the antinociceptive activity of morphine. 

---