A brain-derived neurotrophic factor (BDNF) related system is involved in the maintenance of the polyinnervate Torpedo electric organ.
Target-derived molecules are essential for the maintenance of neuron survival. In the present work, we introduce the electric organ of Torpedo marmorata as a tool for the study of trophic interactions in a polyinervate system. This electric organ maintains a large number of cholinergic terminals on the postsynaptic cell surface. We have observed that a soluble extract derived from the electric organ induces the maturation of Xenopus oocytes injected with presynaptic plasma membranes (PSPM), indicating that a trophic system may exist. Moreover, we have detected a p75NGFR related protein in PSPM by Western blot analysis. These results suggest the presence of a neurotrophin-related system maintaining the polyinnervate electric organ. Furthermore, molecular experiments showed that the brain-derived neurotrophic factor (BDNF) is the neurotrophin operating in our model. Using degenerate oligonucleotides which comprise a conserved fragment of all neurotrophins, we have only amplified by polymerase chain reaction a BDNF fragment. In a similar way, we have amplified and cloned a fragment of the TrkB/C high affinity BDNF receptor. The fact that degenerate oligonucleotides only amplify BDNF allows us to conclude that the polyinnervation is maintained by this neurotrophin either alone or in combination with other trophic factors.
Canals
J M
JM
Departament de Biologia Cellular i Anatomia Patologica, Hospital de Bellvitge, Facultat de Medicina, Universitat de Barcelona, Spain.
Pérez-Navarro
E
E
Ruiz-Avila
L
L
Alberch
J
J
Calvo
N
N
Martín-Zanca
D
D
Marsal
J
J
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019208:Brain-Derived Neurotrophic Factor / Q000502:physiology*; D016922:Cellular Senescence; D004557:Electric Organ / Q000294:innervation*; D008969:Molecular Sequence Data; D009865:Oocytes / Q000502:physiology; D016133:Polymerase Chain Reaction; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D020801:Receptor, Ciliary Neurotrophic Factor; D020800:Receptor, Nerve Growth Factor; D020812:Receptor, trkC; D017475:Receptors, Nerve Growth Factor / Q000032:analysis / Q000378:metabolism; D013574:Synaptosomes / Q000502:physiology; D014020:Tissue Extracts; D014101:Torpedo / Q000033:anatomy & histology / Q000502:physiology*
D019208:Brain-Derived Neurotrophic Factor; D020801:Receptor, Ciliary Neurotrophic Factor; D020800:Receptor, Nerve Growth Factor; D017475:Receptors, Nerve Growth Factor; D014020:Tissue Extracts; D020794:Receptor Protein-Tyrosine Kinases; D020812:Receptor, trkC