Role of mast cell histamine in the formation of rat paw edema: a microdialysis study.
We determined the endogenous histamine concentration in the subplantar space of rat hind paws using an in vivo microdialysis technique. A microdialysis probe was implanted into the rat hind paw and the histamine content in dialysates was measured by high performance liquid chromatography-fluorometry. In wild type (+/+) rats, the histamine output (basal level 25.7 +/- 0.9 pmol/ml) increased 115-, 199- and 426-fold rapidly after subplantar injection of compound 48/80 at doses of 0.5, 5 and 50 microg/paw, respectively. In genetically mast cell-deficient (Ws/Ws) rats, the basal level of histamine was one third of that obtained from +/+ rats, and was not increased by compound 48/80 injection. With this treatment, marked, dose dependent, but relatively gradual development of the paw edema was found in +/+ rats. However, no edema formation was observed in Ws/Ws rats. Histological observations showed neither mast cells nor edema to be present in the paw skin of Ws/Ws rats. These findings indicate the critical role of histamine as a trigger for the development of edema in vivo. In addition, Ws/Ws rats will provide important information as to the roles of mast cells in the inflammatory response.
Guo
Y
Y
Department of Pharmacology, Ehime University School of Medicine, Japan.
Mochizuki
T
T
Morii
E
E
Kitamura
Y
Y
Maeyama
K
K
D000818:Animals; D015550:Cell Degranulation / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D004487:Edema / Q000378:metabolism* / Q000473:pathology; D005470:Fluorometry; D005528:Foot / Q000473:pathology; D006632:Histamine / Q000378:metabolism*; D006636:Histamine Release / Q000187:drug effects; D008297:Male; D008407:Mast Cells / Q000187:drug effects / Q000378:metabolism*; D017551:Microdialysis; D051381:Rats; D011919:Rats, Inbred Strains; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
D003189:p-Methoxy-N-methylphenethylamine; D006632:Histamine