Parkinson’s Disease is characterized by loss of ______ neurons.

Which letter is labeling “repolarization”:

Opening ion channels in a cell membrane will __________.

Serotonin is involved in:

A muscle fiber at rest has high intracellular ______ amounts. 

The ______ phase of a muscle twitch corresponds to removal of Ca2+ from the sarcoplasm. 

_________ are proteins that cause exocytosis of neurotransmitter (via synaptic vesicle fusion with the cell plasma membrane). 

CB1 receptors in the CNS are activated by:

Which letter is labeling “depolarization”:

In a fused tetanus, intracellular levels of ____ increase as this ion accumulates in muscle fibers.