Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BI316 > Lecture 8 > Flashcards

Lecture 8 Flashcards

1
Q

What is a ganglionic transmission?

A

Autonomic ganglia lie outside the CNS and they contain the nerve endings of pre- ganglionic fibres and the cell body of post-ganglionic fibres.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What can be replicated by nicotine?

A

The effect of the transmitter ACh at receptors on the ganglionic neuronal membrane can be replicated by nicotine, i.e. it involves nicotinic cholinoceptors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the two types of drugs acting on the ganglionic transmission?

A
  • Ganglionic stimulants
  • Ganglionic blockers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are Ganglionic stimulants?

A

Drugs that stimulate both sympathetic and parasympathetic ganglia. Drugs directly affect the ganglionic nACH-receptors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What do ganglion-stimulating agents include?

A
  • Nicotine (low concentration)
  • Lobeline
  • Dimethylphenylpiperazinium (DMPP)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the effects of stimulation occurring at both sympathetic and parasympathetic ganglia?

A
  • Tachycardia
  • Increase in blood pressure
  • Increased bronchial, salivary and sweat secretions
  • Variable effects on GI-tract motility
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are Ganglionic blockers?

A

Drugs that block all autonomic ganglia and enteric ganglia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How can ganglionic block be achieved by?

A
  • Prolonged depolarization
  • Interference with the release of ACh
  • Interference with the postsynaptic action of ACh
    (examples in slide 5)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are Ganglion-blocking agents? and what are their effects?

A
  • Nicotine (high concentration)
  • Hexamethonium
  • Trimethaphan
  • Tubocurarine

Effects:
- Hypotension
- Inhibition of secretions
- Paralysis of GI-tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is trimetaphan?

A

It is a short-acting drug given as an i.v. Infusion to produce hypotension during anaesthetic procedures to minimize bleeding during certain kinds of surgery, such as neurosurgery.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is nicotine?

A

Nicotine is a highly toxic alkaloid. It is the prototypical agonist at nicotinic cholinergic receptors, where it dramatically stimulates neurons and ultimately blocks synaptic transmission.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the central effects of nicotine?

A
  • Nicotine dependence
  • Withdrawal
  • De-sensitization symptoms
  • Stimulation of the release of various neurotransmitters in CNS (dopamine, serotonin, GABA, glutamate)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the toxic dose of nicotine?

A

Low nicotine levels in traditional tobacco products:
- Cigarette nicotine; only 1 mg uptake in the body
- Lethal dose: LD = 500 mg nicotine
However, the danger of excess nicotine exposure due to:
- Vaping E-cigarettes
- Pure liquid nicotine
- Concentrated nicotine as a pesticide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does nicotine cause?

A
  • Ganglionic stimulant nicotine causes complex peripheral responses associated with generalized stimulation of the autonomic ganglia.
  • Excitation by low levels of nicotine causes Ganglionic excitation.
  • Blockade by high levels of nicotine causes
    Ganglionic blockade.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the effects of nicotine on the body?

A
  • In tobacco smoke, nicotine is present as a constituent of small tar particles
  • Nicotine is rapidly absorbed through bronchi and lung alveoli
  • Smoking of a single cigarette swiftly yields peak plasma levels of 25-50 ng/ml nicotine
  • Such low concentrations of nicotine act as
    Ganglionic Stimulant of both branches of the ANS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How much nicotine does tobacco contain?

A

0.2 - 5% nicotine

17
Q

What is anti-AChE? and what groups do they fall into?

A
  • They are drugs that inhibit cholinesterase
  • Peripherally acting anticholinesterase drugs fall into three groups based on their duration of action:
  • Short-acting anti-AChE
  • Medium-acting anti-AChE
  • Long-acting anti-AChE
18
Q

Example of Short-acting anti-AChE

A

Edrophonium

19
Q

Example of Medium-acting anti-AChE

A
  • Neostigmine
  • Physostigmine
  • Pyridostigmine
20
Q

Example of Long-acting anti-AChE

A
  • Dyflos
  • Ecothiophate
  • Parathion
21
Q

What is edrophonium?

A
  • Only important short-acting anti-AChE
  • Quaternary ammonium compound
  • Binding to the anionic site of the AChE enzyme
  • An ionic bond formed with AChE is reversible
  • Pharmacological effect is very brief
  • Main usage as a diagnostic tool
22
Q

What is the diagnosis of acquired Myasthenia Gravis?

A

MG is the most common primary muscle disease due to disturbances of neuromuscular transmission. It is an acquired autoimmune disorder of neuromuscular transmission associated with AChR deficiency at the NMJ.

23
Q

What is the Edrophonium test?

A

Improvement of muscle strength by the short-acting anti-AChE is characteristic of MG but does not occur when muscle weakness is due to other causes.

24
Q

Medium-acting anticholinesterases

A

Neostigmine
- Oral drug application for treatment of autoimmune MG
- Reversal of competitive neuromuscular block

Pyridostigmine
- Oral drug application for treatment of autoimmune MG

Physostigmine (Eserine)
- Treatment of glaucoma

25
Q

Long-acting irreversible anticholinesterases

A

Irreversible anticholinesterase:
- Penta-valent phosphorus compounds

  • Organophosphate compounds are highly toxic:
    - War gases
    - Pesticides
    - Limited clinical usage
  • Dyflos: contains a labile fluoride group
  • Parathion: contains a labile organic group
  • Ecothiophatean: contains a labile organic group
  • Inhibitory action: Labile group is released that causes the serine hydroxyl group of AChE to be phosphorylated

BI316 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions