Two studies featuring research from Weill Cornell Medical College have uncovered surprising details about the complex process that leads to the flow of neurotransmitters（神经传导物质） between brain neurons -- a dance of chemical messages so delicate that missteps often lead to neurological dysfunction. A recent Nature Neuroscience study led by Dr. Timothy Ryan, professor of biochemistry at Weill Cornell Medical College, demonstrates that individual neurons somehow control the speed by which they recycle synaptic vesicles（突触泡） that store neurotransmitters before they are released. No one had expected that neurons would have such a powerful "gas pedal," says Dr. Ryan.

Dr. Ryan is also contributing author of a second, Yale University–led study published today in the online edition of Neuron. It shows that the common understanding about how proteins help form these key storage vesicles（囊泡） is flawed.

The two findings help refine science's understanding of the biomechanics that control neurotransmission at the synaptic gap between brain neurons, Dr. Ryan says.

"We are looking under the hood¹ of these machines for the first time," he says. "Many neurological diseases such as Alzheimer's disease, Parkinson's disease, schizophrenia（精神分裂症） and other neurodegenerative and psychiatric disorders² are considered to be synaptopathies -- pathologies of synaptic function. So repairing them will require that we understand how they work."

Both studies focus on synaptic vesicles, which are bubble-like structures that store neurotransmitters within a bi-layer of fatty membranes³ at the synaptic junction⁴.

Scientists know that in order to deliver neurotransmitter messages between cells, the synaptic vesicle merges⁵ with the surface of the brain cell at the synapse⁶ and releases the message. Then these synaptic vesicles, which are in limited supply, must be retrieved⁷, rebuilt and refilled with neurotransmitters, Dr. Ryan says. "Failure to do so would result in the synapse running out of vesicles rather quickly, and proper neurotransmitter function depends on their continuous availability."