1)What is exocytosis and what is its role in neurotransmitter release? 2)Describe the process of vesicle recycling and the various models that have been proposed to explain the recycling process

1)What is exocytosis and what is its role in neurotransmitter release?

2)Describe the process of vesicle recycling and the various models that have been proposed to explain the recycling process. How do these models differ with respect to factors such as speed of recycling, area of the nerve terminal where vesicle membrane retrieval occurs, and the involvement of the protein clathrin and of endosomes?

3)Discuss the concept of a retrograde messenger and how this concept applies to lipid and gaseous transmitters.