Give examples on receptor down and up-regulation?

Downregulation in case of prolonged agonists (chronic use of salbutamol (adrenergic agonist) down regulated beta-receptors- decreased effect of salbutamol in asthmatic pt)) Upregulation in case of prolonged antagonist effect (withdrawal of beta blockers (propranolol) suddenly, causes withdrawal symptoms anxiety palpitation tachycardia, htn,