title: Lowering of interstitial fluid pressure after neurogenic inflammation in mouse skin is partly dependent on mast cells.
abstract: Neurogenic inflammation is known to induce lowering of interstitial fluid pressure (P(if)) in mouse skin. This study examined the possible role of mast cell activation secondary to neuropeptide release in lowering of P(if) by using Kit(W)/Kit(W-v) mice, which are devoid of mast cells, including connective tissue mast cells (CTMCs). P(if) was measured in paw skin of anesthetized (fentanyl-fluanison and midazolam, 1:1) mice with glass capillaries connected to a servo-controlled counterpressure system. In contrast to wild-type mice, intravenous administration of mast cell-activating compound 48/80 induced no lowering of P(if) in Kit(W)/Kit(W-v) mice. Intravenous challenge with substance P (SP), calcitonin gene-related peptide (CGRP), or capsaicin induced a significant (P < 0.05) lowering of P(if) in wild-type mice to -2.16 +/- 0.28, -1.96 +/- 0.11, and -2.22 +/- 0.19 mmHg, respectively, compared with vehicle (-0.49 +/- 0.11 mmHg). In Kit(W)/Kit(W-v) mice the P(if) response to SP was completely abolished (-0.53 +/- 0.32 mmHg) while the response to CGRP and capsaicin was attenuated (-1.33 +/- 0.13 and -1.42 +/- 0.13 mmHg, respectively) although significantly (P < 0.05) lowered compared with vehicle. Immunohistochemical analysis revealed no difference in distribution or density of SP- and CGRP-immunoreactive fibers in paws of Kit(W)/Kit(W-v) compared with wild-type mice. We conclude that lowering of P(if) normally depends on mast cells. However, the sensory nerves can also elicit a lowering of P(if) that is independent of mast cells.
authors.affiliation: Department of Biomedicine, University of Bergen, Bergen, Norway. tine.karlsen@biomed.uib.no
authors.forename: Tine V
authors.initials: TV
authors.lastname: Karlsen
authors.forename: Athanasia
authors.initials: A
authors.lastname: Bletsa
authors.forename: Eli-Anne B
authors.initials: EA
authors.lastname: Gjerde
authors.forename: Rolf K
authors.initials: RK
authors.lastname: Reed
mesh_terms: D018712:Analgesics, Non-Narcotic / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism / Q000494:pharmacology; D002211:Capsaicin / Q000494:pharmacology; D045604:Extracellular Fluid / Q000378:metabolism*; D005260:Female; D007150:Immunohistochemistry; D008407:Mast Cells / Q000502:physiology*; D051379:Mice; D008817:Mice, Mutant Strains; D036421:Nerve Fibers, Unmyelinated / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D009443:Neuritis / Q000276:immunology* / Q000378:metabolism*; D011312:Pressure; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics; D012867:Skin / Q000276:immunology* / Q000294:innervation / Q000378:metabolism; D013373:Substance P / Q000378:metabolism / Q000494:pharmacology
chemical_list: D018712:Analgesics, Non-Narcotic; D013373:Substance P; D019009:Proto-Oncogene Proteins c-kit; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin