Partial Agonism And Competetive Inhibitors

Front 1

Full Agonism

Back 1

The agonist produces a maximal response (i.e. 100%).

Front 2

Antagonism

Back 2

The antagonist binds, but does not proceed to activate the receptor.

Front 3

Partial Agonism

Back 3

Once bound, the agonist produces a SUBMAXIMAL response (i.e. not 100%).

Front 4

Relationship between KD and EC50 in Partial Agonists.

Back 4

The two tend to be close together as a higher concentration of Drug is required to produce a response. Lower affinity.

Front 5

Potency

Back 5

Relates to the affinity of a drug for the receptor and its efficacy. A highly potent drug will produce a strong response (efficacy) with few active DR* complexes (affinity).

Front 6

Salbutamol

Back 6

=Ventolin
Targets B2 receptors.
Causes bronchodilation.

Also targets B1 receptors.
Heart has fewer B2 receptors and more B1 receptors.
Too high concentrations of Salbutamol may induce tachycardia.

Front 7

Types of Antagonism

Back 7

Competetive - binds to receptor.
Non-competetive - binds to a place other than receptor.
Uncompetetive - binds to DR*
Physiological

Front 8

Two types of competetive antagonism.

Back 8

Reversible - no permanent bond.
Irreversible - permanent C bond.

Front 9

Competetive antagonist.

Back 9

Binds to the receptor for the drug but does not activate it, thereby preventing the agonist from binding.

It is surmountable (=increasing [agonist] can counteract the effects)

Dose-response curve shifts to the right, without changing maximal response. KD increases.

Front 10

Dose-Ratio

Back 10

Ratio with which the [agonist] has to be increased to overcome the antagonist.

Front 11

Propanolol

Back 11

Non-selective B adrenergic blocker.
Treats hypertension (= by reducing cardiac muscle contraction)

Front 12

D-tubocurarine

Back 12

Targets nAChr receptors.
Prevents ACh from binding.
NMJ blocker - very dangerous (ganglion blocker).
Previous an anaesthetic. More modern drugs used now.

Front 13

Cimetidine

Back 13

H2 Receptor antagonist.
Reduces gastric acid secretions from stomach.
Reduces ulcer formation.

Front 14

Haloperidol

Back 14

Targets Dopamine (Type II) receptors.
Anti-psychotic - schizophrenia, stops dellusions and hallucinations. This is by blocking Dopamine release in a certain area of the brain.

Front 15

Competetive Irreversible Antagonists

Back 15

Form permanent covalent bonds with the active sites of the receptor. Stops agonist binding completely. Not surmountable. Reduces the maximal response.

Front 16

Naloxone

Back 16

Anti-opioid overdose drug.
Used to reduce respiratory depressant effects of opioids - short lasting.
Competetive atagonist.
Targets opioid receptors in the brain.