signaling process for seperate cell receptor
1. stimulus opens stimulus-sensitive channels, permitting net Na+ entry that produces receptor potential.
2.This local depolarization opens voltage-gated Ca2+ channels.
3.Ca2+ entry triggers exocytosis of neurotransmitter.
4. Neurotransmitter binding opens chemically gated receptor-channels at afferent ending, permitting net Na+ entry.
5. Resultant depolarization opens voltage-gated Na+ channels in adjacent region.
6. Na+ entry initiates action potential in afferent fiber that self-propagates to CNS.