Morphine is an arteriolar vasodilator in man.
Br J Clin Pharmacol
; 67(4): 386-93, 2009 Apr.
Article
en En
| MEDLINE
| ID: mdl-19371311
AIM: The mechanisms of action of morphine on the arterial system are not well understood. The aim was to report forearm vascular responses, and their mediation, to intra-arterial morphine in healthy subjects. METHODS: Three separate protocols were performed: (i) dose ranging; (ii) acute tolerance; (iii) randomized crossover mechanistic study on forearm blood flow (FBF) responses to intrabrachial infusion of morphine using venous occlusion plethysmography. Morphine was infused either alone (study 1 and 2), or with an antagonist: naloxone, combined histamine-1 and histamine-2 receptor blockade or during a nitric oxide clamp. RESULTS: Morphine caused an increase in FBF at doses of 30 microg min(-1)[3.25 (0.26) ml min(-1) 100 ml(-1)][mean (SEM)] doubling at 100 microg min(-1) to 5.23 (0.53) ml min(-1) 100 ml(-1). Acute tolerance was not seen to 50 microg min(-1) morphine, with increased FBF [3.96 (0.35) ml min(-1) 100 ml(-1)] (P = 0.003), throughout the 30-min infusion period. Vasodilatation was abolished by pretreatment with antihistamines (P = 0.008) and the nitric oxide clamp (P < 0.001), but not affected by naloxone. The maximum FBF with pretreatment with combined H1/H2 blockade was 3.06 (0.48) and 2.90 (0.17) ml min(-1) 100 ml(-1) after 30 min, whereas with morphine alone it reached 4.3 (0.89) ml min(-1) 100 ml(-1). CONCLUSIONS: Intra-arterial infusion of morphine into the forearm circulation causes vasodilatation through local histamine-modulated nitric oxide release. Opioid receptor mechanisms need further exploration.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Pletismografía
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Flujo Sanguíneo Regional
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Vasodilatación
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Vasodilatadores
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Antebrazo
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Morfina
Tipo de estudio:
Clinical_trials
Límite:
Adult
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Br J Clin Pharmacol
Año:
2009
Tipo del documento:
Article
País de afiliación:
Irán
Pais de publicación:
Reino Unido