Differential appearance of opiate receptor subtypes in neonatal rat brain

Leslie, Frances M.; Tso, Sharleen; Hurlbut, Diana E.

doi:10.1016/0024-3205(82)90389-7

Cited by 132 publications

(26 citation statements)

References 7 publications

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“…It is more likely however that both morphine and M6G contribute to the analgesic effect and, therefore, lower doses of morphine may be effective in premature neonates. The relationship between morphine, M6G and efficacy requires further study, in particular in the neonatal period when opioid receptors may not be fully developed (Leslie et al, 1982).…”

Section: Discussionmentioning

confidence: 99%

Morphine metabolism in children.

Choonara

McKay

Hain

et al. 1989

Brit J Clinical Pharma

141

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1 The metabolism of morphine was studied in 12 children and nine premature neonates on a continuous infusion of morphine (10-360 ,g kg-' h-1). 2 The mean plasma clearance of morphine was significantly higher in children than neonates (25.7 and 4.7 ml min-' kg-', respectively) (P < 0.01). 3 All the neonates and children had detectable concentrations of morphine-3-glucuronide (M3G) in plasma. All the children and five neonates had detectable concentrations of morphine-6-glucuronide (M6G) in plasma or urine. 4 The M3G/morphine ratios in plasma and urine, and M6G/morphine ratios in urine were significantly higher in children than neonates (P < 0.01), suggesting that morphine glucuronidation capacity is enhanced after the neonatal period. 5There was no difference in the M3G/M6G ratio in children and neonates, indicating a parallel development of both glucuronidation pathways.

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Section: Discussionmentioning

confidence: 99%

Morphine metabolism in children.

Choonara

McKay

Hain

et al. 1989

Brit J Clinical Pharma

141

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“…The stabilization of each subunit in a functional state could be achieved during brain development, depending both on the presence in the membrane of the adapted appropriate transducer and the state of the surrounding lipid. Along this line, it is interesting to note that the ontogenesis of ,u and 8 sites in rat brain are different (30) and that the desipramine-stimulated appearance of cerebroside sulfate in cultures of C6 glial cells is associated with that of stereospecific binding of morphine but not of enkephalins (31). In conclusion, the primary interest of the highly selective photoaffinity reagents proposed in this work could be to identify the polypeptide chains carrying the putatively different opioid receptors, as already carried out for the cholinergic regulator (32).…”

Section: Discussionmentioning

confidence: 99%

Highly selective photoaffinity labeling of mu and delta opioid receptors.

Garbay‐Jaureguiberry¹,

Robichon²,

Dauge³

et al. 1984

Proc. Natl. Acad. Sci. U.S.A.

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We report the synthesis and photolabeling properties of two highly selective ligands for ,u and 8 opioidbinding sites: Tyr-D-Ala-Gly-MePhe(pN3)-Gly-ol (AZ-DAMGE) and Tyr-D-Thr-Gly-Phe(pN3)-Leu-Thr (AZ-DTLET). An irreversible inhibition of the electrically induced contractions of mouse vas deferens is caused by irradiation (at 254 nm) of the muscle strip in the presence of AZ-DTLET (1 nM). This phenomenon is antagonized only at large concentrations (10 FM) of naloxone, in accordance with the well-known lower selectivity of naloxone for 8 sites. Competition experiments with [3H]DAMGE and [3HJDTLET on crude rat brain membranes showed that the azido photoprobes display a similar (AZ-DAMGE) and even a better (AZ-DTLET) selectivity than their respective parent compounds DAMGE and DTLET. Up to 25 nM, AZ-DTLET irreversibly and selectively photolabels the 6 sites of crude rat brain homogenates. Due to its lower affinity AZ-DAMGE provides similar selective photolabeling of the jA sites but at higher concentrations (=0.3 jiM). When

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“…The cerebral cortex of the rat probably contains at least three main subpopulations of opiate-specific binding sites, and these subtypes of brain opiate receptors may proliferate at different rates during postnatal development (12,13). EKC is known to bind readily to both ic and /c-opiate receptors in brain tissue; so, it is not possible to compare relative densities of these two sub-types of cortical opioid receptors during brain develop ment on the basis of binding of this ligand alone.…”

Section: Methodsmentioning

confidence: 99%

“…So, assuming that tifluadom is a selective ti agonist as reported (2,18), our competitive binding results suggest that neonatal cortex may have a higher ratio of ic to It opiate receptors than does adult cortex. As postnatal development progresses, the ratio of tc to p receptors in the cortex may decline due perhaps to a more rapid rate of accumulation of cortical It vs. x receptors (13).…”

Section: Methodsmentioning

confidence: 99%

“…In adult rats, cerebral cortex contains appreciable densities of 6 and is receptors (12). However at birth, there are relatively few 6 receptors in cortex, although the total opioid receptor density in this brain region is already about twenty percent of adult levels (10,13 (14) reported that the (-) isomer of tifluadom has high selectivity for the opiate receptor, but the (+)-isomer of tifluadom binds with about equal affinity to the opiate as well as benzodiazepine recep tors, the present study included parallel measurements of tifluadom binding to ic receptors and to benzodiazepine receptors in the cerebral cortex of neonatal and adult rats. For comparative purposes, we also examined the same cortical binding parameters of two typical benzodiazepines (diazepam and brotizolam*) at the same postnatal ages.…”

Section: Abstract-the Postnatal Development Of 3[h] Ethylketocyclazocmentioning

confidence: 99%

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Differential Postnatal Ontogeny of Opiate and Benzodiazepine Receptor Subtypes in Rat Cerebral Cortex: Binding Characteristics of Tifluadom and Brotizolam

Hill

Watanabe

Shibuya

1984

Japanese Journal of Pharmacology

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Abstract-The postnatal development of 3[H] ethylketocyclazocine (EKC) binding characteristics was examined using membranes from the cerebral cortex of rats at various ages.Binding site affinity did not vary significantly between postnatal days 1 and 90. However, the apparent density of cortical binding sites increased fivefold between birth and adulthood.These results were similar to another ontogenic study of brain opiate receptor binding.Whereas EKC was equally potent as a competitor for 3[H] EKC binding in cortex from neonatal and adult rats, tifluadom was three times more potent in neonatal cortex than in adult cortex as a displacer of specific EKC binding.Brotizolam, a new thienodiazepine and a potent sedative hypnotic, also was distinctly more potent as an inhibitor of 3H-diazepam binding in neonatal rat brain cortex than in adult rat brain cortex.These results suggest that subtypes of benzodiazepine receptors, as well as some opiate receptor subtypes, exhibit different rates of postnatal development.

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Differential appearance of opiate receptor subtypes in neonatal rat brain

Cited by 132 publications

References 7 publications

Morphine metabolism in children.

Morphine metabolism in children.

Highly selective photoaffinity labeling of mu and delta opioid receptors.

Differential Postnatal Ontogeny of Opiate and Benzodiazepine Receptor Subtypes in Rat Cerebral Cortex: Binding Characteristics of Tifluadom and Brotizolam

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