• 7 Trans membrane domains
• extracellular N-terminal domain
• intracellular C-terminal domain
• produces a 2ndary messenger effect

G_i    inhibitory

G_s   stimulatory

G_o   

G_Q

1. adenylyl cyclase- converts ATP into cAMP which regulates energy metabolism
2. phospolipase C-responsible for conversion of PIP₂ to DAG& IP₃
3. Ion channels
4. Rho A/Rho kinase
5. mitogen activated protein kinase

• G-Protein coupled receptors
• kinase lined receptors
• nuclear receptors
• ligand gated ion channels

1. Nicotinic Acetylcholine Receptor(ACh)

-pentameric(5 lobed) assembly of 4 units (α2,β, δ, & ϒ)

-channel opens after two ACh binds to the 2 binding sites

-Na⁺ flow generates AP

   2.GABA_A Receptor

benzodiazepan binds and allosterically modulates the GABA binding site.Gaba binds and acts as a ligand to allow the gated ion channel to open which facilitates the chloride channel to open

• only open once a voltage threshold is reached
• very specific to an ion
• drugs can interact with the channel directly or idirectly

2 examples would be

1. voltage gated Na⁺ channel:blocked by LA,tetrodoxin:Modulated by Veratridine
2. volatge gated Ca²⁺channel:blocked by divalent cation:modulated by dihydropridine

acts as a catalyst to speed up reactions by reducing the activation energy

examples

1. acetylcholinesterase   inhibited by neostigmine
2. cyclo-oxygenase        inhibited by aspirin
3. angiotensin-converting enzyme    inhibited by captopril

• Uniporter-channels(fascilitated diffusion)
• Symporter-2 or more ions moving in the same direction
• antiporter-2 or more ions moving in opposite directions

Personal factors:(RAGG)Related disease,Age,Gender,Genetic factors

Drug Factors:(FADD)Frequency,Administration route,Dose,Duration

Augmented

Bizzare

Continuous

Delayed

E-related to drug withdrawal (think withdrawal symptoms of ecstacy/E)

Failure-unexpected failure of drug therapy

Type A/Augmented

• predictable and common reaction
• rarely results in death

Type B/Bizzare

• rare and unpredictable
• regularily results in death

Cytotoxic

• extention of drugs therapeutic effect
• mainly owing to formation of unstable metabolites from abnormality of metabolism or excretion
• saturation of hepatic enzyme system->generation of free radicals

Drug-disease

• eg. those with peptic ulcer disease being susceptible to bleeding due to Aspirin (and other NSAIDs).-pharmacodynamic
• Sufferers of liver disease are very prone due to poor drug metabolism-pharmacokinetic