title: Effects of histamine-receptor agonists on transvascular fluid and macromolecular efflux in the canine forelimb.
abstract: Histamine increases transvascular fluid and protein efflux in the canine forelimb resulting in edema formation. To clarify the receptor mechanisms of histamine edema, we infused H1 and H2-receptor agonists into the forelimb perfused at constant flow while measuring skin lymph parameters or forelimb weight. The H1-receptor agonist 2(2-pyridyl) ethylamine [PEA] or the H2-receptor agonist 4-methyl histamine (8-40 micrograms/min) singly or in combination fails to increase lymph flow, protein concentration or protein transport. PEA in a dose of 80-400 micrograms/min increases lymph flow, protein concentration and protein transport. 4-Methyl histamine in a dose of 40-200 micrograms/min produces a small but significant decrease in lymph flow and protein transport subsequent to a fall in systemic pressure. 4-Methyl histamine at 40 and 80 micrograms/min produces a progressive and sustained increase in forelimb weight PEA at 40 micrograms/min produces a small increase in forelimb weight which quickly plateaus much like the response seen with acetylcholine (10 micrograms base/min). However, infusion of PEA at 80 micrograms/min progressively increases forelimb weight, similar to that seen with 4-methyl histamine or histamine (1.4 microgram base/min). These data indicate that either H1 or H2-receptor agonists can cause edema formation in the canine forelimb, and imply that histamine edema involves both H1 and H2-receptor interaction.
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001826:Body Fluids / Q000378:metabolism*; D004285:Dogs; D004487:Edema / Q000209:etiology; D005260:Female; D005552:Forelimb; D006339:Heart Rate / Q000187:drug effects; D006632:Histamine / Q000494:pharmacology; D008196:Lymph / Q000187:drug effects / Q000502:physiology; D008297:Male; D008761:Methylhistamines / Q000494:pharmacology; D011506:Proteins / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D011968:Receptors, Histamine / Q000187:drug effects / Q000502:physiology*; D011969:Receptors, Histamine H1 / Q000187:drug effects / Q000502:physiology; D011970:Receptors, Histamine H2 / Q000187:drug effects / Q000502:physiology
chemical_list: D008761:Methylhistamines; D011506:Proteins; D011725:Pyridines; D011968:Receptors, Histamine; D011969:Receptors, Histamine H1; D011970:Receptors, Histamine H2; C025566:4-methylhistamine; D006632:Histamine; C006183:2-(2-aminoethyl)pyridine