Abstract
Microinjections of Leu-enkephalin into the dorsal vagal complex induced hypotension and bradycardia. Both naloxone, given at a dose conferring selectivity for mu receptors, and the delta antagonist ICI 154,129 prevented the cardiovascular effects of Leu-enkephalin. Naloxone was also found to decrease the gain of the baroreflex. These results suggest that Leu-enkephalin is involved in cardiovascular regulation through activation of delta-, and possibly mu-, opioid receptors in the dorsal vagal complex.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Blood Pressure / drug effects
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Cardiovascular System / drug effects*
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Enkephalin, Leucine / analogs & derivatives
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Enkephalin, Leucine / antagonists & inhibitors
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Enkephalin, Leucine / pharmacology*
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Heart Rate / drug effects
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Male
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Microinjections
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Naloxone / pharmacology
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Narcotic Antagonists / pharmacology
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Rats
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Rats, Wistar
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Receptors, Opioid, delta / antagonists & inhibitors
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Receptors, Opioid, mu / antagonists & inhibitors
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Solitary Nucleus / physiology*
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Vagus Nerve / physiology
Substances
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Narcotic Antagonists
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Receptors, Opioid, delta
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Receptors, Opioid, mu
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Naloxone
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Enkephalin, Leucine
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ICI 154129