Fig. 4.

Expression of TrkA in neuron–myocyte co-cultures.A, trkA mRNA in sympathetic neurons, cardiac myocytes, and neuron–myocyte co-cultures by RT-PCR. mRNA extracted from 3-d-old cultures was reverse-transcribed and PCR-amplified using primers specific for trkA. The resulting PCR products were analyzed by agarose gel electrophoresis and ethidium bromide staining. B, Expression of TrkA protein in sympathetic neurons and cardiac myocytes grown in co-culture was analyzed by immunocytochemistry. Neurons and myocytes were grown for 3 d in co-culture, fixed, and stained with the rtrkA antibody. Left panel, Phase-contrast photograph of neuron–myocyte co-culture after fixation. Right panel, TrkA staining. The arrow indicates a myocyte.