Abstract |
Previously, it has been observed that mu-opioid receptors contribute to while kappa-opioid receptors oppose pial artery dilation in response to hypoxia. The present study was designed to investigate the contribution of delta 1- and delta 2-opioid receptor activation to hypoxia-induced pial vasodilation. Newborn pigs equipped with a closed cranial window were used to measure pial artery diameter and collect cortical periarachnoid CSF for assay of opioids. Hypoxia increased CSF leucine enkephalin (a delta -agonist) from 36 +/- 6 to 113 +/- 17 pg/ml (n = 5). Hypoxia-induced pial artery vasodilation was attenuated during moderate hypoxia (PaO2 approximately 35 mm Hg), while this response was blunted during severe hypoxia (PaO2 approximately 25 mm Hg), by the delta 1-opioid receptor antagonist 7-benzylidenenaltrexone (BNTX; 10(-8) M) (23 +/- 2 vs. 13 +/- 2 and 34 +/- 6 vs. 10 +/- 3% for moderate and severe hypoxia in the absence and presence of BNTX, respectively; n = 5). In contrast, the delta 2-opioid receptor antagonist naltrindole (10(-9) M) blunted pial vasodilation during moderate hypoxia, but only attenuated the vasodilator response during severe hypoxia (22 +/- 2 vs. 8 +/- 2 and 33 +/- 4 vs. 23 +/- 4% for moderate and severe hypoxia in the absence and presence of naltrindole, respectively; n = 5).(ABSTRACT TRUNCATED AT 250 WORDS)
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Authors | W M Armstead |
Journal | Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism
(J Cereb Blood Flow Metab)
Vol. 15
Issue 3
Pg. 539-46
(May 1995)
ISSN: 0271-678X [Print] United States |
PMID | 7714013
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)
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Chemical References |
- Benzylidene Compounds
- Enkephalins
- Narcotic Antagonists
- Oligopeptides
- Receptors, Opioid, delta
- Receptors, Opioid, mu
- deltorphin II, Ala(2)-
- 7-benzylidenenaltrexone
- Naltrexone
- Enkephalin, D-Penicillamine (2,5)-
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Topics |
- Animals
- Animals, Newborn
- Benzylidene Compounds
(pharmacology)
- Enkephalin, D-Penicillamine (2,5)-
- Enkephalins
(pharmacology)
- Female
- Hypoxia
(metabolism)
- Male
- Naltrexone
(analogs & derivatives, pharmacology)
- Narcotic Antagonists
(pharmacology)
- Oligopeptides
(pharmacology)
- Pia Mater
(blood supply)
- Receptors, Opioid, delta
(agonists)
- Receptors, Opioid, mu
(antagonists & inhibitors, metabolism)
- Swine
- Vasodilation
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