title: Receptor mechanisms of serotonin-induced prenodal lymphatic constriction in the canine forelimb.
abstract: Numerous endogenous vasoactive agents have been shown to cause lymphatic smooth muscle contraction. In this study, we assessed the ability of serotonin (5-HT) to alter lymphatic smooth muscle activity and elucidated the receptor mechanisms of 5-HT's actions. Both intralymphatic and intra-arterial administration of 5-HT significantly increased lymphatic smooth muscle activity in lymphatics perfused at constant flow, as indicated by an increase in lymphatic perfusion pressure. The 5-HT-induced increase in lymphatic perfusion pressure is attenuated but not blocked by the intra-arterial infusion of phentolamine, suggesting the involvement of alpha-adrenoreceptors and 5-HT receptors. Intralymphatic infusion of the 5-HT2-receptor-agonist alpha-methylserotonin significantly increased lymphatic perfusion pressure, either alone or when administered into an alpha-receptor blocked preparation, whereas the 5-HT1-receptor-agonist carboxyami-dotryptamine maleate did not effect the prenodal lymphatics. These data indicate that the lymphatic smooth muscle contraction produced by 5-HT is mediated both by lymphatic alpha-adrenoreceptors and 5-HT2 receptors.
authors.affiliation: Department of Physiology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814-4799, USA.
authors.forename: D E
authors.initials: DE
authors.lastname: Dobbins
mesh_terms: D000818:Animals; D004285:Dogs; D005260:Female; D008208:Lymphatic System / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000502:physiology*; D010646:Phentolamine / Q000494:pharmacology; D011312:Pressure; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D011985:Receptors, Serotonin / Q000502:physiology*; D012701:Serotonin / Q000031:analogs & derivatives / Q000494:pharmacology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology
chemical_list: D011942:Receptors, Adrenergic, alpha; D011985:Receptors, Serotonin; D017366:Serotonin Receptor Agonists; C042390:alpha-methylserotonin; D012701:Serotonin; D010646:Phentolamine