Types of Synapse Flashcards

Flashcards reviewing the different types of synapses, their terminology, and associated processes.

Synaptic Cleft

The space between the presynaptic and postsynaptic neurons where neurotransmitters are released and bind to receptors.

Presynaptic Neuron

The neuron that transmits a signal to another neuron across a synapse.

Postsynaptic Neuron

The neuron that receives a signal from another neuron across a synapse.

Electrical Synapse

A type of synapse that allows direct transfer of ions through gap junctions, enabling fast and non-rectifying transmission.

Connexon

A channel made of 6 connexin subunits for ion transfer between cells.

Chemical Synapse

A type of synapse that uses neurotransmitters to transmit signals across the synaptic cleft, involving a synaptic delay.

Synaptic Delay

The time taken for a signal to cross a chemical synapse, typically 0.5-2 ms.

Vagusstoff

Otto Loewi's term for the substance released by the vagus nerve that inhibits heart rate, later identified as acetylcholine.

SNARE Proteins

Proteins including synaptobrevin, SNAP-25, and syntaxin involved in vesicle docking and fusion with the presynaptic membrane for neurotransmitter release.

Synaptotagmin

A vesicle protein that senses calcium and triggers the fusion of the vesicle with the membrane, leading to neurotransmitter release.

Quantal Release

The release of neurotransmitters in discrete packets or quanta, each corresponding to the contents of a single vesicle.

MEPP (Miniature Endplate Potential)

Small, spontaneous postsynaptic potentials that occur even in the absence of nerve stimulation, due to the release of a single quantum of neurotransmitter.

Quantal Content

The number of quanta released per action potential at a synapse.

Clathrin

A protein involved in vesicle recycling by forming a coat around the vesicle during endocytosis.

ω-agatoxin IVA

A toxin from the funnel web spider that blocks P/Q-type voltage-gated calcium channels.

Botulinum Toxin (Botox)

A toxin produced by Clostridium botulinum that cleaves SNARE proteins, inhibiting neurotransmitter release.

ω-conotoxin MVIIC

A toxin from the cone snail that blocks N-type voltage-gated calcium channels.

α-bungarotoxin

A toxin from the banded krait that blocks nicotinic acetylcholine receptors.

Physostigmine (Eserine)

An acetylcholinesterase inhibitor found in the Calabar bean, used to treat myasthenia gravis.

Myasthenia Gravis (MG)

An autoimmune disease in which nicotinic receptors are attacked by antibodies, causing muscle weakness.