CNS Basics Flashcards
What are the respective potentials of the common ions?
K+ = -75mV Na+ = 55mV Cl- = 69mV
What are the ways mono-amines can get deactivated?
Diffuse
Reuptake - NERT/DAT
Degraded - MAO and COMT
What is an EPSP?
Excitatory Post-Synaptic Potential - where the membrane becomes more positive lowering threshold for AP
Increases conductance of Na or Ca
What is an IPSP?
Increases the conductance of negative ions increasing the polarity - increasing the threshold for AP
What neuropeptide is always co-localized with dopamine neurons?
Neurotensin - present to add variety to dopamine release for different signals
How is neurotensin synthesized?
Made from a 170 AA peptide that is cleaved into two neuropeptides and packaged into a vesicle in the golgi transported to terminal end of neuron.
What is required to release Neurotensin?
Calcium dependent, but requires MORE calcium compared to a regular vesicle release. Thus only is released in rapid firing/high intensity stimulation.
What is unique about the vesicle of Neurotensin?
Vesicle can leave the neuron anywhere on the membrane, the vesicle is more dense, does not need special proteins to be released out of the cell.
How is the release of Neurotensin and NE different?
Neurotensin vesicles are larger, more dense, can be released anywhere and the cell does not recapture them.
NE - smaller, released only at active zone, recycled and refilled.
How is neurotensin inactivated?
Nonspecific peptides cleave it in the synapse and can diffuse away. No reuptake.
How are neurotensin receptors arranged?
They are more diffusely located on the post-synaptic neuron because neurotensin can activate further away. less direct. High affinity for neurotensin, low amount required to bind for G-coupled activation.
