Abstract
The effects of highly selective antagonists to μ-, δ-, and κ-opioid receptor subtypes on hyperosmotic- or angiotensin II (AII)-induced arginine vasotocin (AVT) release were investigated in chicks. Plasma levels of AVT increased about 1.5-fold after the administration of 1.5 M NaCl (200 μl, ip) or 100 ng AII (5 μl, icv). The administration of the μ-antagonist naloxonazine and the κ-antagonist nor-Binaltorphimine further elevated plasma levels of AVT stimulated by hypertonic NaCl or AII. These effects of μ- and κ-opioid receptor antagonists on AVT release were dose dependent. Nor-Binahorphimine enhanced hyperosmotically stimulated plasma levels of AVT at a lower dose than that of naloxonazine. Conversely, the δ-selective antagonist naltrindole did not significantly affect AVT secretion. None of the opioid receptor antagonists influenced basal plasma levels of AVT. Therefore, these results suggest that μ- and δ-opioid receptors are involved in hyperosmotic- and AII-induced AVT release, and the effect of the κ-opioid receptor antagonist in the AVT release stimulated by hyperosmolality is strong compared to that of the μ-opioid receptor antagonist, (C) 2000 Academic Press.
Original language | English |
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Pages (from-to) | 365-372 |
Number of pages | 8 |
Journal | General and Comparative Endocrinology |
Volume | 118 |
Issue number | 3 |
DOIs | |
Publication status | Published - Jun 2000 |
Externally published | Yes |
Keywords
- Angiotensin II
- Arginine vasotocin
- Chicks
- Hypertonic stimulation
- Naloxonazine
- Naltrindole
- Nor-BNI
- Opioid receptor
ASJC Scopus subject areas
- Animal Science and Zoology
- Endocrinology