Abstract:

Objective   To elucidate the direct effect of brain-derived neurotrophic factor (BDNF) on contraction of mice intestinal muscle strips and to investigate whether the effect of BDNF on intestinal contraction is mediated through the tyrosine kinase receptor B (TrkB)- phospholipase C (PLC)/ inositol triphosphate (IP3) pathway. Methods   Longitudinal muscle (LM) strips of ileum, proximal colon and distal colon from C57bl/6 mice were prepared. The contraction of LM was recorded with a tension transducer. To investigate the contractile effect of BDNF on LM strips, two different doses of BDNF(1×10-8 and 1×10-7mol/L) were added to the muscle strips. To investigate the effects of antagonists of the TrkB-PLC/IP3 signal pathway on the contraction of muscle strips induced by BDNF, LM strips were pretreated with TrkB (1×10-8mol/L), neomycin (1×10-5mol/L) and heparin (1×10-5mol/L) before administration of BDNF. Results   BDNF excited the contraction of LM from the ileum, proximal colon and distal colon of mice (P<0.05). Pretreatment with TrkB (1×10-8mol/L), neomycin (1×10-5mol/L) and heparin (1×10-5mol/L) dramatically attenuated the excitatory effect of BDNF (1×10-7mol/L) on the contraction of LM strips (P<0.05). Conclusion   BDNF excites the contraction of mice intestinal muscle strips, and the antagonists of the TrkB-PLC/IP3 signal pathway attenuate the excitatory effect of BDNF, which highlights the important role of BDNF and the TrkB-PLC/IP3 signal pathway in promoting the gut motility.

Key words: Brain-derived neurotrophic factor; Signal pathway; Smooth muscle; Contraction; Mice