Preliminary study on sarcoglycan sub-complex in rat cerebral and cerebellar cortex.

The sarcoglycan sub-complex is a protein system which plays a key role in sarcolemma stabilization during muscle activity. Although numerous studies have been conducted on this system, there are few data about its localization in non-muscular tissues. On this basis we carried out an indirect immunofluorescence study on normal rat cerebral and cerebellar cortex. In particular, we carried out single localization reactions to analyze if these proteins are present in brain and double localization reactions between sarcoglycans and either SMI-32 or GFAP to verify if they are expressed both in neurons and glial cells. We found that all tested sarcoglycans are present both in cerebral and cerebellar cortex and that they are expressed both in neurons and glial cells. The typical staining pattern of all sarcoglycans is represented by "spot-like" fluorescence, with spots of 0.5-2 microm average diameter laid out mainly around the soma of the cells. The main difference about sarcoglycans expression between cerebral and cerebellar cortex is that in the cerebellar cortex the sarcoglycans positivity is detectable only in an area which is likely to correspond to Purkinje cells layer. The presence of sarcoglycans in cerebral and cerebellar cortex and their disposition mainly around the soma of the cells suggest a role of these proteins in cellular signalling and in regulating postsynaptic receptor assembly mainly in axo-somatic synapses.