EXPRESSION OF NEUROTROPHIN RECEPTORS IN RAT SUPERIOR CERVICAL GANGLIA

Valle-Leija P, Arias R, Cancino A, Cifuentes F, Morales MA.

Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Autónoma de México (UNAM), México D.F.



Neurotrophins such as nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) act through the tropomyosin-related receptor tyrosine kinases (trk) and the pan-neurotrophin receptor (p75) to regulate complex developmental and functional properties of neurons. While NGF can activate trkA and p75 in rat superior cervical ganglia (SCG) to regulate synaptic transmission, BDNF can only act through p75 because of the absence of a functional and complete trkB receptor. Contrary to what has been reported, we found expression of full length trkB in neurons from SCG in cultures and tissue by immunolabeling and immunoblot. Although the expression of trkB in adult tissue was present in a low percentage of neurons when compared to trkA and p75, in co-cultures of neurons with cardiomyocites the expression was very high. Western blot analysis showed that both truncated and full length forms of trkB are present in SCG tissue. In addition expression of the full length trkB transcript isoform was found by rtPCR and RNA sequencing.