Lecture 23. Pharmacology Flashcards
What do neurotransmitters do at synapses ?
Diffuse short distances and bind to receptors on target cells
What are motor neurons ?
Final common pathway by which various regions of the CNS exert control over skeletal muscle activity
What areas are influenced by motor neurons ?
Spinal cord, motor regions of the cortex, basal nuclei, cerebellum and brainstem
What is an example of a neurotransmitter ?
Acetylcholine
What are acetylcholine receptors at the neuromuscular junction ?
Nicotonic
What happens when acetylcholine receptors are activated ?
Ion channels open allowing influx of current and depolarisation of cell
What is the function of acetylcholinesterase ?
Inactivates acetylcholine, ends the end-plate potential and the action potential and resultant contraction
What does black widow spider venom do ?
Cause explosive release of acetylcholine resulting in prolonged depolarisation and respiratory failure
What does botulinim do ?
Blocks the release of acetylcholine causing flacid paralysis
What does curare do ?
Blocks the action of acetylcholine at receptor sites (antagonist competitive with acetylcholine)
What do organophosphates (sarin) do ?
Prevent inactivation of acetylcholine resulting lung muscle paralysis
What is a modified part of sympathetic nervous system ?
Adrenal medulla
What is the adrenal medulla ?
A modified sympathetic ganglion that does not give rise to postganglionic fibres
What prompts secretion of hormones into blood ?
Stimulation of preganglionic fiber
What are the two neurotransmitters in the autonomic nervous system ?
- Acetylcholine
2. Noradrenaline
Where is the sympathetic acetylcholine secreted from ?
Pre-ganglionic neuron
Where is the sympathetic noradrenaline secreted from ?
Post-ganglionic neuron
What causes the release of adrenaline from adrenal gland ?
Noradrenaline
In the parasympathetic system, where is acetylcholine released from ?
Both pre-ganglionic and post-ganglionic neurons
What are the cholinergic receptors ?
- Nicotinic receptors
2. Muscarinic receptors
What is the function of the cholinergic receptor ?
Binds acetylcholine
Where is nicotinic receptor found on ?
Postganglionic cell bodies of all autonomic receptors
Where is the muscarinic receptor found ?
On the effector cell membrane
What is the function of andrenergic receptors ?
Binds noradrenaline and adrenaline
What is the function of the receptor agonist ?
Binds to same receptor as neurotransmitter and elicits an effect that mimics that of a neurotransmitter
What is the function of the receptor antagonist ?
Binds to the receptor and blocks the neurotransmitter response
What can regions of CNS involved in control of autonomic activities be influenced by ?
Prefrontal cortex through its involvement with emotional expression characteristic of individual’s personality
What plays an important role in integrating autonomic, somatic and endocrine responses ?
Hypothalamus
What is the region directly responsible for autonomic output ?
Medulla within brain stem
What are the autonomic reflexes integrated at spinal cord level ?
Urination, defecation and erection
What are two examples of the use of autonomic nervous system pharmacology in clinical practice ?
- Bronchodilator
2. Metroprolol
What is the bronchodilator - salbutamol ?
B2- adrenergic agonist
Where are the B2-adrenergic receptors found ?
The predominant receptors on bronchial smooth muscle
How do bronchodilator drugs act ?
They act on receptors to mimic the effect of the endogenous neurotransmitter, widening bronchioles and making it easier to breathe
What is the metoprolol ?
An anti-hypertensive that blocks B1 adrenergic receptors
Where are B1 adrenergic receptors found ?
In heart muscle cells
What do B-blockers do ?
Block the effect of sympathetic nerves, decreasing heart rate and helping to lower blood pressure
What are some common neurotransmitters ?
- Acetylcholine
- Dopamine
- Noradrenaline
- Adrenaline
- Serotonin
- Histamine
- Glycine
- Glutamate
- Aspartate
- GABA
What is the blood brain barrier ?
How blood vessels are arranged in the brain
What makes the blood brain barrier effective ?
Tight junctions between endothelial cells lining cerebral blood vessels
