Collaboration of fibronectin matrix and neurotrophin in regulating spontaneous transmitter release at developing neuromuscular synapses in Xenopus cell cultures

Integrins mediate cell-extracellular matrix connection and are particularly important during neuronal development. We here investigated the regulation of fibronectin (FN) matrix and neurotrophins on the embryonic synaptic tra nsmission. Spontaneous synaptic currents (SSCs) were recorded from innervat ed myocytes of 1-day-old Xenopus cultures by whole-cell recordings. The SSC increasing action of alpha,beta -methylene adenosine triphosphate was enha nced in neurons grown on FN substratum, which was further potentiated by ch ronic treatment with brain-derived neurotrophic factor (BDNF). The SSC incr easing action of thapsigargin, carbonyl cyanide m-chlorophenylhydrazone and N-methyl-D-aspartate was also markedly potentiated in neurons grown on FN- coated glass coverslips and chronically treated with BDNF. FN matrix or BDN F alone only exerts slight potentiation on the SSC increasing action of the se three drugs. Our results suggest that FN matrix can collaborate with neu rotrophin in regulating synaptic transmission at developing motoneurons, wh ich may play an important role in the maturation of embryonic neuromuscular junction. (C) 2001 Published by Elsevier Science Ireland Ltd.