Central Nervous System and Analgesics

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Questions and Answers

What is the primary action of naloxone in relation to opioid receptors?

It fully activates opioid receptors with morphine-like effects.

It serves as a pure antagonist at all opioid receptor sites. (correct)

It acts as a partial agonist on opioid receptors.

It has no effect on opioid receptors.

How does naltrexone differ from naloxone in terms of duration of action?

Naltrexone is only effective when injected.

Naltrexone has a longer duration of action than naloxone. (correct)

They both have the same duration of action.

Naltrexone has a shorter duration of action than naloxone.

Which statement correctly describes the properties of naloxone?

Naloxone is primarily used in chronic pain management.

Naloxone has no morphine-like properties as it is a pure antagonist. (correct)

Naloxone has partial agonist properties at opioid receptors.

Naloxone mimics the effects of morphine.

In which situation would naloxone be most appropriately used?

To reverse opioid overdose in emergency situations. Signup and view all the answers

What distinguishes naloxone's mechanism from that of opioids?

Naloxone competes with opioids for receptor sites without activating them. Signup and view all the answers

What is the primary mechanism described for the sedation process?

Decrease in noradrenaline release Signup and view all the answers

Which area of the brain is primarily affected by the sedation mechanism?

Brain stem Signup and view all the answers

What effect does decreased noradrenaline release have on neuron activity?

Inhibits impulse transmission Signup and view all the answers

Which neurotransmitter's release is mainly decreased to induce sedation?

Noradrenaline Signup and view all the answers

What is the primary effect of sedation on neuron function?

Depression of neurons Signup and view all the answers

What is one of the primary mechanisms of action of Phenytoin?

Suppresses repetitive neuronal firing Signup and view all the answers

How does Phenytoin affect the release of glutamate?

Attenuates action and release of glutamate Signup and view all the answers

What effect does Phenytoin have on abnormal neuronal impulses?

Reduces propagation of abnormal impulses Signup and view all the answers

Phenytoin is classified as which type of drug?

Antiepileptic Signup and view all the answers

What role does Phenytoin play in relation to neuronal firing?

Suppresses repetitive neuronal firing Signup and view all the answers

Which of the following substances is classified as an analeptic?

Nikethamide Signup and view all the answers

What is the main action of strychnine on the nervous system?

Blocks the receptors for glycine Signup and view all the answers

What effect does strychnine have on reflex excitability?

Increases reflex excitability of the spinal cord Signup and view all the answers

The use of which analeptic is associated with increased tonic convulsions of all limbs?

Strychnine Signup and view all the answers

What type of muscle response is most commonly affected by strychnine's mechanism of action?

Powerful muscles acting at the joint Signup and view all the answers

What is the method of administering peripheral nerve block anaesthesia?

Injection of solution around a nerve trunk Signup and view all the answers

Where is epidural anaesthesia administered in relation to the duramater?

Adjacent to, but outside the duramater Signup and view all the answers

Which technique is primarily used in dentistry?

Peripheral nerve block anaesthesia Signup and view all the answers

What is a key characteristic of epidural anaesthesia?

Can involve slow infusion via a cannula Signup and view all the answers

Which of the following statements about peripheral nerve block anaesthesia is true?

It involves injection at a specific nerve trunk location Signup and view all the answers

What is the primary action of morphine related to the emetic chemoreceptor trigger zone (CTZ)?

It stimulates the vomiting center. Signup and view all the answers

Which physiological effect is commonly associated with morphine's action on the pupils?

Severe miosis (constricted pupils) Signup and view all the answers

Which reflex is stimulated by morphine due to its effects on the spinal cord?

Monosynaptic spinal reflex (stretch reflex) Signup and view all the answers

What is a potential side effect of morphine aside from nausea and vomiting?

Respiratory depression Signup and view all the answers

What is the role of the occlulomotor center in the context of morphine administration?

It regulates miosis (pupil constriction). Signup and view all the answers

Study Notes

Naloxone and Opioid Receptors

Naloxone is an opioid antagonist, which means it blocks the effects of opioids at their receptors.
Naloxone has a short duration of action, typically lasting 30 to 90 minutes.
Naltrexone, also an opioid antagonist, has a much longer duration of action, lasting for 24 to 72 hours.
Naloxone is a pure antagonist, meaning it only blocks opioid receptors and does not have any agonist activity.
Naloxone is most appropriately used in situations where opioid overdose is suspected. It can reverse respiratory depression and other symptoms of opioid overdose.
Naloxone's mechanism differs from that of opioids because it binds to the same receptors as opioids, but it does not activate them. Instead, it blocks the binding of opioids to these receptors.

Sedation Mechanism

Sedation is primarily achieved through the reduction of neuronal activity in the central nervous system.
The reticular activating system (RAS) in the brainstem is a key area affected by the sedation mechanism.
Decreased noradrenaline release leads to decreased neuronal activity and promotes sedation.
The release of GABA is mainly decreased during sedation.
Sedation primarily affects neuronal function by reducing the firing rate of neurons and decreasing their excitability.

Phenytoin and Neuronal Function

Phenytoin, an anticonvulsant medication, primarily works by blocking the repetitive firing of neurons.
Phenytoin reduces the release of glutamate, an excitatory neurotransmitter, which helps to decrease neuronal excitation.
Phenytoin can also suppress abnormal neuronal impulses, helping to reduce seizures.
Phenytoin is classified as a sodium channel blocker.
Phenytoin's role in neuronal firing is to stabilize neuronal membranes and limit excessive or repetitive firing.

Analeptics and the Nervous System

Analeptics are stimulants of the central nervous system.
Strychnine, an analeptic, acts on the spinal cord by blocking the inhibitory neurotransmitter glycine.
Strychnine increases reflex excitability, leading to muscle spasms and convulsions.
The use of strychnine is associated with increased tonic convulsions of all limbs.
Strychnine primarily affects the skeletal muscles, causing muscle spasms and tetany.

Anaesthesia Techniques

Peripheral nerve block anaesthesia involves injecting a local anaesthetic around a nerve or group of nerves, blocking their ability to transmit pain signals.
Epidural anaesthesia is administered into the epidural space, located between the dura mater and the vertebral canal.
Infiltration anaesthesia is the primary technique used in dentistry. It involves injecting local anesthetic directly into tissues near the site of surgery.
Epidural anaesthesia's key characteristic is that it produces a segmental block, meaning only the nerves supplying specific areas of the body are affected.
Peripheral nerve block anaesthesia can provide complete anaesthesia for specific regions of the body without the need for general anaesthesia.

Morphine and its Effects

Morphine's primary action related to the emetic chemoreceptor trigger zone (CTZ) is to stimulate this area, leading to nausea and vomiting.
Morphine commonly causes pupillary constriction (miosis).
Morphine stimulates the cough reflex due to its effects on the spinal cord.
Constipation is another potential side effect of morphine administration.
The oculomotor center in the brainstem is responsible for controlling pupillary size and other eye movements. Morphine affects this center, causing pupillary constriction.

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Description

This quiz covers essential concepts of the Central Nervous System (CNS) and the classification of drugs acting on it, particularly analgesics. You'll learn about the differences between opioid and non-opioid analgesics, their mechanisms of action, and potential for addiction. Perfect for students studying neuroscience or pharmacology.