GDNF and glioblastoma: According to the first mechanism, Car activates intestinal epithelial cells and causes them to secrete trophic factors that reach the brain and activate brain function [62], while the second mechanism of carnosine activation of brain function is based on the ability of the peptide (1–10 mM) to permeate the blood brain barrier and activate glial cells causing the secretion of NGF, BDNF, NTF4 and GDNF in human primary glioblastoma cell line(U-87 MG) [60].