Sensory responses of human skin to synthetic histamine analogues and histamine.
The potential for itch production in human skin of the synthetic analogues of histamine, 2-methyl histamine (an H1-receptor agonist) and 4-methyl histamine and dimaprit (H2-receptor agonists) has been studied in vivo and compared with histamine. Itch thresholds for 2-methyl histamine were consistently much higher than for histamine (P < 0.001). The H1-receptor antagonist chlorpheniramine raised the itch thresholds to 2-methyl histamine and histamine significantly (P < 0.001). Pruritus was not obtained with either 4-methyl histamine or dimaprit. No evidence of synergism between 2-methyl histamine and either 4-methyl histamine or dimaprit was found. The results suggest that histamine-induced pruritus is mediated in part through the H1-receptor and in part via an additional (but probably non-H2) mechanism.
D000328:Adult; D002744:Chlorpheniramine / Q000494:pharmacology; D017259:Dimaprit; D005260:Female; D006632:Histamine / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008761:Methylhistamines / Q000009:adverse effects*; D011537:Pruritus / Q000139:chemically induced* / Q000209:etiology; D011969:Receptors, Histamine H1 / Q000502:physiology; D011970:Receptors, Histamine H2 / Q000502:physiology; D012867:Skin / Q000187:drug effects / Q000378:metabolism; D013890:Thiourea / Q000009:adverse effects*
D008761:Methylhistamines; D011969:Receptors, Histamine H1; D011970:Receptors, Histamine H2; D002744:Chlorpheniramine; C025566:4-methylhistamine; D006632:Histamine; D013890:Thiourea; C026259:2-methylhistamine; D017259:Dimaprit