Lecture 2: Basic Pharmacology Flashcards
What are the 3 main types of physiological mediators?
Neurotransmitters such as NA, ACh
Hormones such as adrenaline which is released from the adrenal medulla and acts on the heart.
Local hormones/autacoids which are hormones which are released and act upon the same/nearby tissue e.g. Prostaglandins
What are receptors?
Recognition molecules for soluble physiological mediators.
Normally membrane bound although there are some exceptions e.g. …
What is the process of ligand gated ion channel receptor signalling?
Ligand binds to the ionotropic receptor causing the receptor to change its shape resulting in either hyperpolarisation or depolarisation as a result of allowing or inhibiting ion movement. This results in cellular effects.
Ionotropic receptor signalling occurs within milliseconds. E.g. Nicotinic ACh receptor.
What is the process of a g-protein coupled receptor?
Ligand binds to the metatrobic receptor, activating a secondary messenger (such as cAMP). This results in calcium release, protein phosphorylation and other effects resulting in cellular effects.
Metabotropic signalling occurs within seconds e.g. Muscarinic ACh receptor.
What is the process of kinase linked receptor signalling?
Ligand binds to kinase receptor causing a protein phosphorylation. This leads to gene transcription, resulting in protein synthesis and cellular effects.
Kinase linked receptor signalling occurs within hours e.g. Cytokine receptors
What is the process of nuclear receptor signalling?
Ligand binds to receptor in the nucleus resulting in gene transcription, protein synthesis and cellular effects.
This occurs within hours e.g. Oestrogen receptor
What are the types of G-protein coupled receptors?
Gs
Gi/o
Gq
What are receptors for each mediator divided into?
Subtypes
How are subtypes determined?
By structural differences and therefore transduction differences, and location
What are the 3 main different muscarinic subtypes?
M1 ( neural)
M2 (cardiac)
M3 (glandular/smooth muscle)
What are the main locations of M1 (neural) muscarinic receptors?
1) Autonomic ganglia glands: gastric, salivary etc.
2) Cerebral cortex
What are the main locations of M2 (cardiac) muscarinic receptors?
Heart: Atria
CNS: widely distributed
What are the main locations of M3 (glandular/smooth muscle) muscarinic receptors ?
Exocrine glands: gastric, salivary etc.
Smooth muscle: GIT, eye, airways, bladder
Blood vessels: endothelium, CNS
What are the cellular responses resulting from M1 (neural) muscarinic receptors?
Increased IP3, DAG
Depolarisation
Excitation (slow epsp)
Decreased K+ conductance
What are the cellular responses resulting from M2 (cardiac) muscarinic receptors?
Decreased cAMP
Inhibition
Reduced Ca2+ conductance
Increased K+ conductance
