MAST-CELL SPECIFIC PROTEASES IN RAT-BRAIN - CHANGES IN RATS WITH EXPERIMENTAL ALLERGIC ENCEPHALOMYELITIS

Mast cell populations were identified within brain parenchyma by their specific proteases, using antibodies for immunohistochemistry and ELI SAs, and riboprobes were developed for in situ hybridisation. Connecti ve tissue mast cells expressing rat mast cell protease I (RMCPI) mRNA and immunoreactivity were observed in thalamus and showed no degranula tion at 3, 8 and 13 days after induction of experimental allergic ence phalomyelitis (EAE). Mucosal-like mast cells were clearly demonstrated in control rats by measuring RMCPII and by visualising cells expressi ng RMCPII mRNA and immunoreactivity. At day 13, but not 3 and 8 post i mmunisation, the number of RMCPII-expressing cells markedly increased in the EAE-induced group, mainly within brainstem and spinal cord clos e to inflammed blood vessels. The markers of histaminergic neurons wer e marginally affected 13 days after immunisation and the increase of [ H-3] histamine synthesis elicited by the H-3-receptor antagonist, thio peramide, was not modified in any region of the brain.It is concluded that the cerebral RMCPII-expressing mast cells could play a role durin g EAE.