Modification by Capsaicin and Compound 48/80 of Dye Leakage Induced by Irritants in the Rat

Abstract

1Concentration-related dye leakage produced by intracutaneous injections of irritants was measured in rats by an Evans blue technique. 2 In rats pretreated with a total dose of 50 mg capsaicin over 4 days, the response to capsaicin, formalin, HC1, KCI, prostaglandin E,, bradykinin and bradykinin with prostaglandin E1 (10-6 M) were greatly reduced, the responses to histamine and 5-hydroxytryptamine were slightly reduced and those to adenosine 5'-triphosphate (ATP) and compound 48/80 were unaffected.3 Pretreatment with intracutaneous injections of compound 48/80 (0.5 ,ug, 24 and 48 h previously) recuded the responses to ATP, compound 48/80, HCI, KCI, prostaglandin E1, and bradykinin but did not affect those to histamine, 5-hydroxytryptamine or bradykinin with prostaglandin E1 (106 M). 4 Responses to capsaicin and formalin produced spotted blueing extending over a large area and were suppressed by compound 48/80 in the smaller pretreated area only. Capsaicin responses were reduced with larger doses of compound 48/80 (total dose 15 gg).

Participation of Serotonin in Capsaicin-Induced Mouse Ear Edema

“…These results clearly indicate that 5-HT partly participates in the development of capsaicin-induced mouse ear edema via 5-HT2 receptors. 5-HT is known to induce plasma extravasation by a direct action on the microvasculature in rats (25,26) and to produce vasodilation via 5-HT1 receptors on peripheral blood vessels (27). A recent report (28) suggested that in addition to 5-HT receptors, endogenous nitric oxide is involved in 5-HT-induced increase in vascular permeability in mouse skin.…”

Topical capsaicin pretreatment inhibits axon reflex vasodilatation caused by somatostatin and vasoactive intestinal polypeptide in human skin

“…Topical capsaicin produces local desensitization of skin to chemogenic noxious agents (Jansco, 1960), possibly by depleting SP in nerve terminals (see Carpenter & Lynn, 1981). Parenteral capsaicin reduces both neurogenic plasma extravasation (Jansco, 1960;Arvier, Chahl & Ladd, 1977;Gamse, Holzer & Lembeck, 1980) and SP levels in rat skin (Gamse et al, 1980;Hayes & Tyers, 1980). SP-related peptides which fail to produce a flare when injected into human skin also fail to release histamine from rat mast cells in vitro (Foreman & Jordan, 1982).…”

THE EFFECTS OF SENSORY DENERVATION ON THE RESPONSES OF THE RABBIT EYE TO PROSTAGLANDIN E1, BRADYKININ AND SUBSTANCE P

“…Jampol, Axelrod & Tessler (1976) found that the effects of topical nitrogen mustard on the rabbit eye were reduced after prior infection with herpes simplex and inferred that an axon reflex was necessary to mediate the response. Using the technique of Jancso (1960) of desensitization by capsaicin, Arvier, Chahl & Ladd (1977) showed that in the rat skin, noxious substances including formaldehyde, bradykinin and prostaglandin act directly and exclusively on sensory nerve endings. From these findings they suggested that a 00 Macmillan Journals Ltd 1980 0007-118 8/80/070495-08 $01.00 humoral substance was released which either liberated histamine and 5-hydroxytryptamine from mast cells or acted directly on the blood vessels to cause vasodilatation.…”