Binder H J, Laurenson J P, Dobbins J W
Am J Physiol. 1984 Oct;247(4 Pt 1):G432-6. doi: 10.1152/ajpgi.1984.247.4.G432.
The mechanism of opioid peptide stimulation of active Na and Cl absorption in rabbit ileum is not known. Since vasoactive intestinal peptide (VIP) modulation of electrolyte transport is mediated by specific membrane receptors, these experiments sought to determine whether membrane receptors for opioid peptides are present on rabbit ileal enterocytes. Although we found specific binding both of radiolabeled opioid peptides to homogenates of cerebrum and ileal myenteric plexi and of 125I-VIP to ileal enterocytes, specific binding of radiolabeled opioid peptides to either ileal enterocytes or their homogenates was not identified. In parallel studies, tetrodotoxin, an inhibitor of neurotransmission, did not alter VIP-stimulation of Cl secretion but inhibited D-Ala2-methionine-enkephalinamide-induced electrolyte absorption. These studies suggest that opioid peptide stimulation of active Na and Cl absorption is mediated by an unidentified intermediary agonist.
阿片肽刺激家兔回肠主动吸收钠和氯的机制尚不清楚。由于血管活性肠肽（VIP）对电解质转运的调节是由特定的膜受体介导的，因此这些实验旨在确定家兔回肠肠上皮细胞上是否存在阿片肽的膜受体。尽管我们发现放射性标记的阿片肽与大脑匀浆和回肠肌间神经丛均有特异性结合，并且125I-VIP与回肠肠上皮细胞也有特异性结合，但未发现放射性标记的阿片肽与回肠肠上皮细胞或其匀浆有特异性结合。在平行研究中，神经传递抑制剂河豚毒素并未改变VIP对氯分泌的刺激作用，但抑制了D-丙氨酸2-甲硫氨酸脑啡肽酰胺诱导的电解质吸收。这些研究表明，阿片肽刺激主动吸收钠和氯是由一种未确定的中间激动剂介导的。
