title: Effects of AVP and DDAVP on histamine-induced increases in macromolecular permeability in the hamster cheek pouch.
abstract: The effects of histamine alone and in the presence of AVP or DDAVP on microvascular permeability to macromolecules was evaluated in the superfused hamster cheek pouch. FITC-Dextran (MW 70,000) was employed as a macromolecular tracer to quantitate the increase in macromolecular permeability produced by the topical application of histamine. Intra-vital light microscopy was utilized to quantitate and localize FITC-D extravasation sites along the vascular tree, and fluorimetric measurement of the FITC-D concentration in the suffusate (S) and plasma (P) was used to calculate the FITC-D S/P ratio to quantitate the increase in macromolecular permeability. The infusion of histamine for 5 minutes at a rate which produced a suffusate histamine concentration of 1 X 10(-5) M produced a marked increase in the number of venular FITC-D leakage sites, the [FITC-D]s, and the FITC-D S/P ratio. These effects of histamine were prevented by treatment with either AVP or DDAVP which was infused at a rate sufficient to produce a suffusate concentration of 1 X 10(-8) M. AVP produced profound vasoconstriction whereas DDAVP prevented the histamine-induced increase in the formation of venular FITC-D leakage sites, the [FITC-D]s, and FITC-D S/P ratio without producing vasoconstriction. These data suggest that the antagonism of the histamine-induced increase in macromolecular permeability by AVP and DDAVP is not dependent on vasoconstriction per se, but rather is attributable to the stimulation of a vasopressin receptor on the venular endothelial cell which is identical to or similar to the vasopressin receptor mediating the anti-diuretic effects of these agents.
mesh_terms: D000287:Administration, Topical; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002610:Cheek / Q000098:blood supply / Q000187:drug effects; D006224:Cricetinae; D003894:Deamino Arginine Vasopressin / Q000031:analogs & derivatives* / Q000494:pharmacology; D003911:Dextrans; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives*; D005452:Fluoresceins; D006632:Histamine / Q000008:administration & dosage / Q000494:pharmacology*; D006633:Histamine Antagonists / Q000494:pharmacology; D046911:Macromolecular Substances / Q000378:metabolism; D008297:Male; D008647:Mesocricetus; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects
chemical_list: D003911:Dextrans; D005452:Fluoresceins; D006633:Histamine Antagonists; D046911:Macromolecular Substances; C015219:fluorescein isothiocyanate dextran; D001127:Arginine Vasopressin; C025161:vasopressin, deamino-homo-Arg-; D006632:Histamine; D003894:Deamino Arginine Vasopressin; D016650:Fluorescein-5-isothiocyanate