Potentiation of the osmosensitive release of taurine and D-aspartate from SH-SY5Y neuroblastoma cells after activation of M3 muscarinic cholinergic receptors.

The ability of muscarinic cholinergic receptors (mAChRs) to regulate the volume-sensitive efflux of two organic osmolytes, namely, taurine and d-aspartate, from human SH-SY5Y neuroblastoma cells has been examined. Incubation of the cells with hypoosmolar buffers resulted in an efflux of both osmolytes, with the threshold for release occurring at approximately 225 mOsM for taurine and d-aspartate. Inclusion of oxotremorine-M (Oxo-M), a muscarinic agonist, resulted in a marked enhancement of the volume-dependent efflux of both osmolytes and increased the threshold osmolarity for taurine and d-aspartate release to 340 (isotonic) and 320 mOsM, respectively.