Transferrin can alter physiological properties of retinal neurons.
The role of transferrin as a possible neurotransmitter was examined in cultured chick retinal cells. Brief exposure to transferrin caused a dramatic and transient increase in intracellular calcium levels in approximately 20% of the total population of cultured retinal neurons. The increase in intracellular calcium was observed in cell bodies and neuronal processes. Electrophysiological analysis of a subset of the population, bipolar-like neurons, demonstrated that more than half of these cells responded to the application of transferrin with a transient membrane depolarization. Under voltage clamp conditions, the currents evoked by transferrin were similar to glutamate in that they both displayed non-linear voltage dependence. Furthermore, acute transferrin exposure resulted in a 200% increase in the amount of Na+ independent [3H]glutamate binding observed in these cultures. These results suggest that transferrin may function as a neurotransmitter or neuromodulator in the developing vertebrate nervous system.
Department of Biological Sciences, Rutgers University, Piscataway, NJ 08855.
A G
AG
Hyndman
P E
PE
Hockberger
G D
GD
Zeevalk
J A
JA
Connor
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D002642:Chick Embryo; D005971:Glutamates / Q000378:metabolism / Q000494:pharmacology; D018698:Glutamic Acid; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter / Q000378:metabolism; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000502:physiology*; D014168:Transferrin / Q000494:pharmacology*
D005971:Glutamates; D018377:Neurotransmitter Agents; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter; D014168:Transferrin; D018698:Glutamic Acid; D002118:Calcium