GPCRs

1. G proteins
   1. Enzyme activation
2. Phosphorylation Cascades

Nota:

• How selective a drug is for a receptor

1. Clean Drug

   Nota:

   • Only acts on one receptor
2. Dirty drug

   Nota:

   • Drug acts on many receptors 

Nota:

• Results in: 1) turning off the receptor  2) removing it from the surface 

1. Receptor turns off

   Nota:

   • Normally by phosphorylating receptor 
2. Removing it from the surface

   Nota:

   • Called internalisation  Can be short or long term  Long term causes increase or decrease in receptor expression

Nota:

• Cell recieves multiple signals and turns it into a response, normally when there are opposing effects on 2nd messengers 
• Net effect is the sum of the 2 receptor types (e.g. pars/sympathetic systems)