Cat Nictitating Membrane
DEMO
What is the Ganglion?
The postganglionic neurone in the SCG receives three types of innervation (Greengard, 1976). Acetylcholine released from preganglionic nerve terminals activates:
- Nicotinic cholinoceptors on the postganglionic neurone to produce a fast Excitatory Post-Synaptic Potential (EPSP)
- Muscarinic cholinoceptors on the postganglionic neurone to produce a slow EPSP and prolonged depolarization
- A dopaminergic interneurone leading to the release of dopamine which activates alpha-2 receptors on the postganglionic neurone to produce a slow Inhibitory Post-Synaptic Potential (IPSP). The released dopamine also activates dopamine (D1) receptors which enhances the muscarinic response. Administration of dopamine causes a long-lasting (several hours) depolarization (Libet & Tosaka, 1970).