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Survival of Chick Embryonic Sensory Neurons in Culture Is Supported by Phorbol Esters
Author(s) -
Bhave Sanjiv V.,
Malhotra Ravindra K.,
Wakade Taruna D.,
Wakade Arun R.
Publication year - 1990
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1990.tb01917.x
Subject(s) - protein kinase c , sensory neuron , protein kinase a , cytosol , protein data bank (rcsb pdb) , neurotrophin , sensory system , phorbol , biology , biochemistry , nerve growth factor , neuron , neurotrophic factors , embryo , enzyme , medicine , endocrinology , microbiology and biotechnology , neuroscience , receptor
Sensory neurons of the chick embryo are supported in culture by several neurotrophic factors, including the phorbol esters. Because phorbol esters are known to activate one of the second messengers, namely, protein kinase C, it was of interest to see if the neurotrophic action of phorbol 12,13‐dibutyrate (PDB) was related to the activation of protein kinase C in sensory neurons. Sensory neurons were obtained from dorsal root ganglia of 10‐day‐old chick embryos and maintained in a serum‐free medium for several days to quantify survival and analyze protein kinase C activity. PDB (30 n M ) supported the survival of ± 50% of the total number of neurons plated. This value was comparable to that supported by nerve growth factor (NGF; 40 ng/ml). If PDB and NGF were added together, there was no additive effect on the survival. The protein kinase C activity of the particulate and cytosolic fractions of sensory neurons supported by NGF for 3 days was 1.26 ± 0.1 and 2.9 ± 0.32 pmol/min/mg of protein, respectively. In contrast, neurons supported by PDB showed an ± 500% increase in enzyme activity in their particulate fraction. The enzyme activity of the cytosolic fraction was decreased by ± 40%. If NGF‐supported neurons were treated with PDB (30 n M ) for 15 min, protein kinase C activity increased > 400% in the particulate fraction, whereas an ± 50% decrease was observed in the cytosolic fraction. The protein kinase C value, expressed as a ratio of the activities in the particulate to cytosol fractions, showed large increases after phorbol treatment. The ratio was 0.43 in NGF‐supported neurons and increased to 3.57 in PDB‐supported neurons. NGF‐supported neurons treated with PDB for 15 min had a ratio of 4.1. Phorbol‐13‐acetate did not support the survival, nor did it increase protein kinase C activities in NGF‐supported neurons. Because sensory neurons contain substantial amounts of choline acetyltransferase (ChAT) activity, we compared ChAT activity in NGF‐ and PDB‐supported sensory neurons. Values were 21.93 ± 3.7 and 22.09 ± 4.6 pmol of acetylcholine formed/min/mg of protein, respectively. These results suggest that neurotrophic action of PDB on chick sensory neurons is probably mediated through protein kinase C. The present data also suggest that NGF and PDB act on the same subpopulation of sensory neurons of the dorsal root ganglia of the chick to support their survival in culture.