Neurokinin Biosynthesis and Peptide Degradation

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What was Substance P initially isolated from?

GI tract

Salivary glands

Brain

Gut (correct)

Who discovered enkephalins while searching for endogenous compounds that mimicked the effect of morphine?

Gaddum

Kosterlitz (correct)

Von Euler

Euler and Gaddum

What is the name of the peptides that include Substance P, NKA, and NKB?

Neurokinins

Enkephalins

Opioid peptides

Tachykinins (correct)

What technique led to an explosion in the discovery of bioactive neuropeptides in the CNS, PNS, and ENS?

Immunohistochemistry Signup and view all the answers

What is the function of Substance P in the nervous system?

Sensory neurotransmitter Signup and view all the answers

What is the origin of the name 'Substance P'?

From the phrase 'powder' in French Signup and view all the answers

Where are neuropeptides expressed, apart from in the nervous system?

In the gut and salivary glands Signup and view all the answers

In which organisms are neuropeptides expressed?

In mammals, vertebrates, and invertebrates Signup and view all the answers

What is the primary function of Dale's Principle in the context of neurotransmission?

To propose the idea of a single neuron storing and releasing neurotransmitters from all its terminals Signup and view all the answers

Which of the following scientists is credited with proposing the co-transmitter hypothesis?

Geoff Burnstock Signup and view all the answers

What is the term for the process by which neurotransmitters are removed from the synaptic cleft?

Degradation/inactivation Signup and view all the answers

What is the primary function of neuropeptide Y (NPY) in the context of neurotransmission?

The exact function of NPY is not specified in the text Signup and view all the answers

What is the significance of the work of Henry Dale in the context of neurotransmission?

His research led to the development of Dale's Principle Signup and view all the answers

What is the term for the process by which neurotransmitters are prepared for release?

Packaging Signup and view all the answers

What is the significance of John Eccles' proposal in 1957?

It suggested that neurons have a single neurotransmitter Signup and view all the answers

What is the crucial structural motif involved in receptor interaction?

Amino group Signup and view all the answers

Which enzyme is responsible for degrading met- and Leu-enkephalins?

Enkephalinase Signup and view all the answers

What is the effect of Phosphoramidon on NKs?

It inhibits NEP, exaggerating NK effects Signup and view all the answers

What determines which peptidase breaks down a neuropeptide?

The structure of the peptide Signup and view all the answers

What is the result of NPY being degraded by dipeptidyl peptidase IV?

A biologically active fragment is formed Signup and view all the answers

What is the role of NEP in neurokinin degradation?

It is the major inactivator of neurokinins Signup and view all the answers

What is the effect of post-secretory processing on receptor selectivity?

It modifies receptor selectivity Signup and view all the answers

What is the potential therapeutic application of NK receptor antagonists?

Anti-inflammatory agents Signup and view all the answers

What is the primary function of angiotensin converting enzyme (ACE)?

Hydrolyzing enkephalins, SP, and neurotensin Signup and view all the answers

Which of the following is NOT a characteristic of neuropeptide degradation?

Neuropeptides can be re-uptaked and re-used Signup and view all the answers

What is the result of cleavage of two amino acids from NPY?

Change in the pharmacology of NPY Signup and view all the answers

What is the primary mechanism of release in response to low-frequency action potentials?

Exocytosis of small clear vesicles (SSVs) Signup and view all the answers

What is the characteristic of the autonomic neuroeffector junction?

Non-specialized, unlike NMJ Signup and view all the answers

What is the primary difference between neuropeptide release and classic transmitter release?

Neuropeptides are released from LDCVs, while classic transmitters are released from SSVs Signup and view all the answers

What is the role of dipeptidyl peptidase in neuropeptide metabolism?

Cleavage of NPY to modify receptor selectivity Signup and view all the answers

What is the result of high-frequency action potentials or pulsatile nerve stimulation on neuropeptide release?

Co-release of both classic transmitters and neuropeptides from SSVs and LDCVs Signup and view all the answers

What is the primary difference in response times between neuropeptides and fast neurotransmitters?

Neuropeptides respond in seconds or minutes, while fast neurotransmitters respond in milliseconds Signup and view all the answers

What type of receptors are peptide receptors generally coupled to?

G protein-coupled receptors (GPCRs) Signup and view all the answers

What is the effect of degrading NPY by DPPIV?

It preferentially stimulates Y2 receptors Signup and view all the answers

What is the importance of the amidated C-terminal of NPY?

It is crucial for peptide activity Signup and view all the answers

What is the effect of NPY on intracellular cAMP levels?

It decreases intracellular cAMP levels Signup and view all the answers

What is the difference between NPY and pancreatic polypeptide (PP) in terms of their effects on Y receptors?

NPY stimulates Y1 and Y2 receptors, while PP stimulates Y4 receptors Signup and view all the answers

What is the structure of NPY in solution?

A hairpin-shaped structure Signup and view all the answers

What is the effect of NPY on intracellular Ca++ levels?

It can increase or decrease intracellular Ca++ levels depending on the receptor type Signup and view all the answers