Tumor necrosis factor-alpha prevents interleukin-1 beta from augmenting capsaicin-induced vasodilatation in the rat skin.
The effect of tumor necrosis factor-alpha (TNF alpha) and tumor necrosis factor-beta (TNF beta) on the capsaicin-induced increase in cutaneous blood flow was investigated in anaesthetized rats. Skin blood flow was measured by laser-Doppler flowmetry. Intraplantar subcutaneous injections of 5-500 pg TNF alpha and 50-5000 pg TNF beta had no effect on local blood flow, whereas 5000 pg TNF alpha induced a transient hyperaemia. However, neither the pretreatment with TNF alpha (5-5000 pg) nor that with TNF beta (50-5000 pg) enhanced the vasodilatator response to intraplantar capsaicin (0.03 micrograms; 0.1 microgram), whereas 50 pg interleukin-1 beta augmented the capsaicin-induced hyperaemia (P < 0.05). This enhancement of the cutaneous hyperaemic response to capsaicin was absent when interleukin-1 beta (50 pg) was co-injected with TNF alpha (500 pg or 5000 pg). The vasodilatation caused by calcitonin gene-related peptide or bradykinin was not altered by 500 pg or 5000 pg TNF alpha. These data indicate that TNFs, in contrast to interleukin-1 beta, do not amplify the hyperaemic response to afferent nerve stimulation with capsaicin but reverse the augmentation mediated by interleukin-1 beta.
Herbert
M K
MK
Department of Anaesthesiology, University of Würzburg, Germany.
Hering
S
S
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001920:Bradykinin / Q000494:pharmacology; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology; D002211:Capsaicin / Q000494:pharmacology*; D005260:Female; D006940:Hyperemia / Q000139:chemically induced; D007375:Interleukin-1 / Q000494:pharmacology*; D008233:Lymphotoxin-alpha / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000098:blood supply*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects*
D007375:Interleukin-1; D008233:Lymphotoxin-alpha; D014409:Tumor Necrosis Factor-alpha; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin; D001920:Bradykinin