1 The influence of lipopolysaccharide (LPS)-induced sepsis on the various m
ast cell phenotypes of rat dura mater were examined both by immunohistochem
ical and biochemical methods.
2 Three different populations of mast cells were identified in control rats
: connective tissue type mast cells (CTMC) which contain rat mast cell prot
easel (RMCP1), histamine, serotonin and heparin, mucosal type mast cells (M
MC) which contain RMCP2, histamine and serotonin, and intermediate type whi
ch contains both RMCP1 and RMCP2 and probably various proportions of amines
and heparin.
3 LPS (25 mg kg(-1) i.p.) caused changes in the proportions of the various
types of mast cells. The number of MMC and intermediate type mast cells sig
nificantly increased and the number of mast cells immunopositive for both h
eparin and serotonin significantly decreased. Biochemical analysis showed t
hat the histamine concentration of dura increased while its serotonin conce
ntration decreased.
4 While vasoactive intestinal peptide (VIP) (25 ng kg(-1) i.p.) appears to
potentiate LPS effects on dura mater mast cells, non-selective inhibition o
f nitric oxide (NO) synthase by Ng-nitro-L-arginine methyl ester (L-NAME) (
30 mg kg(-1) i.p.) did not influence sepsis-induced mast cell changes.
5 These findings suggest that mast cells of dura mater may play a role in b
rain protection during sepsis.