Brain-derived neurotrophic factor is stored in human platelets and released by agonist stimulation.

摘要: Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family, plays critical roles in survival, growth, and maintenance brain peripheral neurons. We report presence BDNF protein human platelets its release upon agonist stimulation. The content washed varied widely, from 3.5 to 67 ng/4 x 10(8) platelets, averaging 25.2 +/- 21.2 (mean+/-SD). concentration platelet-poor plasma was low (1.7+/-1.7 ng/ml, n = 11). Thrombin, collagen, Ca++ ionophore A23187, shear stress each induced rapid platelets. Up only half platelet secreted stimulation, suggesting that may have non-releasable pool BDNF, or released binds recognition site on surface is internalized, as occurs with serotonin. However, cognate receptor, TrkB, not detected Nevertheless, ability bind shown by FACS analysis confocal microscopy binding apparent internalization [125I]-BDNF A very high affinity (Kd 130 10(-15) M, approximately 80 sites/platelet) moderately 20 nM, 3750 were identified. two megakaryocytic cell lines, DAMI Meg-01, 0.1% measured No mRNA Northern blotting these lines pituitary gland also ruled out source for since rat did decrease 2 weeks after hypophysectomy. Thus, acquired megakaryocyte gland, but probably other sources via blood circulation. Platelets appear bind, store activation at traumatic injury facilitate repair nerves tissues contain TrkB.