Developmental change of mu opioid receptors in neonatal guinea pig brain stem
1995; Elsevier BV; Volume: 85; Issue: 1 Linguagem: Inglês
10.1016/0165-3806(94)00206-f
ISSN1872-6755
AutoresLaine J. Murphey, George D. Olsen,
Tópico(s)Receptor Mechanisms and Signaling
ResumoOpioid receptor binding of morphine-6-β-d-glucuronide (M6G), morphine and [3H][D-Ala2, N-methylPhe4-Glyol5] enkephalin (DAMGO) were determined in neonatal guinea pigs. Pontomedullary membranes specifically bound [3H]DAMGO, which was displaced by M6G and morphine. The KI for M6G and morphine were 15.1 nM and 5.0 nM, respectively, and did not change between day 3 and day 7 after birth. KD for [3H]DAMGO binding was constant (1.1nM), however Bmax increased from 62.2 to 88.3 fmol/mg protein between days 3 and 7 (P < 0.01). This 42% increase in mu receptors may play a role in the increased potency of M6G respiratory effects for guinea pigs during the first week after birth.
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