biology

Synaptosome

Synaptosome is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Synaptosome rather than just read about it. In short: A synaptosome is an isolated synaptic terminal from a neuron. Synaptosomes are obtained by mild homogenization of nervous tissue under isotonic conditions and subsequent fractionation using differential and density gradient centrifugation.

Key takeaways

Synaptosome belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Synaptosome to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Synaptosome from memory before moving on to harder problems.

Reference excerpt

A synaptosome is an isolated synaptic terminal from a neuron. Synaptosomes are obtained by mild homogenization of nervous tissue under isotonic conditions and subsequent fractionation using differential and density gradient centrifugation. Liquid shear detaches the nerve terminals from the axon and the plasma membrane surrounding the nerve terminal particle reseals. Synaptosomes are osmotically sensitive, contain numerous small clear synaptic vesicles, sometimes larger dense-core vesicles and frequently one or more small mitochondria. They carry the morphological features and most of the chemical properties of the original nerve terminal. Synaptosomes isolated from mammalian brain often retain a piece of the attached postsynaptic membrane, facing the active zone. Synaptosomes were first isolated in an attempt to identify the subcellular compartment corresponding to the fraction of so-called bound acetylcholine that remains when brain tissue is homogenized in iso-osmotic sucrose. Particles containing acetylcholine and its synthesizing enzyme choline acetyltransferase were originally isolated by Hebb and Whittaker (1958) at the Agricultural Research Council, Institute of Animal Physiology, Babraham, Cambridge, UK. In a collaborative study with the electron microscopist E. George Gray from University College London, Victor P. Whittaker eventually showed that the acetylcholine-rich particles derived from guinea-pig cerebral cortex were synaptic vesicle-rich pinched-off nerve terminals. Whittaker coined the term synaptosome to describe these fractionation-derived particles and shortly thereafter synaptic vesicles could be isolated from lysed synaptosomes. Synaptosomes are commonly used to study synaptic transmission in the test tube because they contain the molecular machinery necessary for the uptake, storage, and release of neurotransmitters. In addition they have become a common tool for drug testing. They maintain a normal membrane potential, contain presynaptic receptors, translocate metabolites and ions, and when depolarized, release multiple neurotransmitters (including acetylcholine, amino acids, catecholamines, and peptides) in a Ca2+-dependent manner. Synaptosomes isolated from the whole brain or certain brain regions are also useful models for studying structure-function relationships in synaptic vesicle release. Synaptosomes can also be isolated from tissues other than brain such as spinal cord, retina, myenteric plexus or the electric ray electric organ. Synaptosomes may be used to isolate postsynaptic densities or the presynaptic active zone with attached synaptic vesicles. Accordingly, various subproteomes of isolated synaptosomes, such as synaptic vesicles, synaptic membranes, or postsynaptic densities can now be studied by proteomic techniques, leading to a deeper understanding of the molecular machinery of brain neurotransmission and neuroplasticity.

Illustrations

Worked examples

Example 1 — a first encounter with Synaptosome

Start with the simplest possible case. Write down what Synaptosome claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Synaptosome before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Synaptosome ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Synaptosome

In research: Synaptosome appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Synaptosome in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Synaptosome is common in secondary-school and first-year university syllabi. It links to neighbouring topics Neurology, so understanding it makes those chapters shorter.
In everyday life: Look for Synaptosome outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Synaptosome in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Synaptosome means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Synaptosome out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Synaptosome in simple terms?

Why does Synaptosome matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Synaptosome?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Synaptosome.