The effect of neonatal treatment with capsaicin on focal arteriolar insudation.
There is evidence that peptide neurotransmitters (e.g., substance P, neurokinin A, vasoactive intestinal peptide, calcitonin gene-related peptide) from sensory nerves play a part in vasoregulation. We examined the effect of neonatal treatment with capsaicin, a procedure that causes permanent impairment of primary sensory neurons, on a recently described arteriolar response to inflammation, focal arteriolar insudation (FAI). FAI occurs at a distance from the site of injury, in arterioles supplying that area, and is first observed 6 hr after onset of inflammation and maximally at 24 hr; the affected arterioles show dilation, with increased endothelial permeability and occasional smooth muscle cell damage. In our model, inflammation is induced by implanting a sterile plastic disk in the connective tissue superficial to the rat cremaster muscle. When carbon black is injected intravenously 24 hr later, FAI in the cremaster arterioles can be detected on light microscopy as areas of carbon extravasation; and the length of affected segments is morphometrically measured. The capsaicin-pretreated group showed a marked decrease in FAI compared to the controls. Mean FAI in the capsaicin group (12 animals) was 1.8 +/- 2.4 (SD) mm/cremaster compared to 5.6 +/- 5.1 for the control group (12 animals). P less than 0.003. These results provide evidence that this arteriolar response to inflammation is modulated in part by capsaicin-sensitive neurons.
Chung
E S
ES
Department of Pathology and Medicine, University of Massachusetts Medical School, Worcester 01655.
Leeman
S E
SE
Cuénoud
H F
HF
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001160:Arterioles / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D001835:Body Weight / Q000187:drug effects; D002211:Capsaicin / Q000494:pharmacology*; D004108:Dilatation, Pathologic / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology; D005490:Focal Infection / Q000139:chemically induced* / Q000473:pathology / Q000503:physiopathology; D007249:Inflammation / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects / Q000473:pathology; D051381:Rats; D011919:Rats, Inbred Strains
D002211:Capsaicin