Voltage-gated calcium channels, mitochondria and synaptic vesicles are all found where?

In the presynaptic terminal

What are dynein and kinesin and what is a distinctive feature that differentiates them?

They are both motor proteins which are needed for active transport of chemical signaling; kinesin acts in the anterograde direction while dynein acts in the retrograde direction

How do electrical synapses function?

Neurons are actually fused by gap junctions and the electrical signal flows directly from one neuron to the next

What are gap junctions good for in neurons?

Synchronization of networks, coordinated release of hormones, coordinated breathing rhythms and fast escape behaviors

In vertabrates, where do gap junctions most often exist?

In the retina, cardiac muscle, brain areas such as the cerebellum and astrocytes

What is the C-bend behavior in fish and how can it be used?

It starts with muscular signaling to bend the head and tail in a desired direction and is followed by a quick burst of forward movement; this can be used for an escape response or for prey capture as two examples

What are mauthner cells and what are they primarily involved in?

They underly the C-bend behavior in fish; they lie near the midline of the hindbrain and are large, fast-conducting axons

How is the mauthner cell signaling pathway set up?

It is nearly optimized in order to send signals along very quickly with large, fast-conducting neurons and excitatory synapses

How do post-synaptic responses differ between chemical and electrical junctions?

Electric synapses are closer in amplitude to the pre-synaptic depolarization (at least in crayfish, from Furshpan & Potter, 1959)

What are the key functional differences between electrical and chemical synapses?

Electric synapses are used to synchorize firing where synchronization is critical while chemical synapses are used more for diversity and plasticity

Neurophysiology, neuroanatomy and biochemistry & molecular biology are all methods by which to do what?

Study synaptic mechanisms

What types of chemicals initiate neuronal signaling in chemical pathways?

Amino acids, amines and peptides can all carry neurological signals

What are the 4 criteria of a neurotransmiter?

1: it is present at the teriminal 2: it is released upon an action potential 3: its receptors are activated when it's released 4: its release is "calcium dependent" (although this does not actually apply across the board)

What is required for the fusing of a vesicle membrane to the presynaptic terminal?

Calcium influx

Describe the general process by which small molecule signals such as neurotransmitters are made

The neuron can send slow, anterograde signaling of enzymes which are then used to recycle old, degraded neurotransmitters

How are peptide transmitters sent down through the neuron?

They are packed in dense core vesicles and can travel up to 400mm/day; propeptides are proteolytically processed while in transit then put into their proper forms once at the terminal

How do different frequencies of signals impact neuronal signaling?

Low frequencies will result in small vesicle fusion events while higher frequencies with higher rates of action potentials will result in the release of dense core vesicles

How did Loewi's experiment demonstrate chemical neurotransmission?

A chemical or multiple chemicals from the first, suppressed heart made the second heart beat faster when it was exposed to the resulting net solution

What is QUANTA?

It's the amount of NT in a single vesicle

What evidence is there for the "vesicle hypothesis" of neurotransmission?

There is a strong positive correlation between vesicle fusions and the # of quanta released

What effect does introducing a calcium channel blocker have on the post-synaptic action potential?

Under control conditions, there is a fairly quick rise in the postsynaptic membrane potential which reduces somewhat slowly over time but there is no depolarization at all in the presence of a calcium channel blocker

When calcium is injected into presynaptic neurons, it results in a postsynaptic response. What does this indicate?

That calcium triggering plays a role in presynaptic transmitter release

Vesicle fusions increase the plasma membrane so what else do they also impact?

They increase membrane capacitance

What is a "kiss and run" release and what function does it serve?

It releases a very small amount of charge into the extracellular domain without actually fusing its membrane and thus without step-wise increasing the membrane capacitance

What did Heuser & Reese (1973) show with horseradish peroxidase (HRP) in regards to synaptic vesicles?

If you wash away extracellular HRP and then wait for one hour, new vesicles containing HRP will form showing that new vesicles form if the old ones aren't being used

What chemical is used to coat the insides of vesicles that get taken back up from postsynaptic membranes?

Clathrin

What protein is involved in pinching off clathrin-coated synaptic vesicles and what is important to note about it?

The protein, dynamin, requires ATP to fully pinch off the vesicle

Synaptobrevin, syntaxin, synaptotagmin and SNAP-25 are all proteins that serve what function?

They trigger calcium-dependent vesicle fusion