DISTRIBUTION OF ADRENOCEPTOR SUBTYPES

Contaction

Contaction (dilates pupil) mydriasis

Erects hair

Alpha-1 actions in

• Most vascular smooth muscle (innervated)

• Pupillary dilator muscle

• Pilomotor smooth muscle

Ejaculation

Contraction

Increase secretion

Alpha-1 actions in

• Penis, seminal vesicles ejaculation

• Bladder sphincter contraction

• Sweat glands (apocrine) stress

Yes to constrcit it

Can you give an alpha-1 receptor to benign prostatic hyperplasia?

Probably multiple

Aggregation

Inhibition of transmitter release

Alpha 2 receptor actions in

• Postsynaptic CNS adrenoceptors

• Platelets

• Adrenergic and cholinergic nerve terminals

No to stroke px bc it can cause more obstruction, Yes to hypertension

Can you give alpha-2 receptor in stroke patients and hypertension?

Contraction

Inhibition of lipolylsis

Alpha 2 receptor actions in

• Some vasular smooth muscle

• Fat cells

When the synaptic vesicle releases norepinephrine, some binds to alpha-2 receptor that can cause an inhibition of adenylyl cylase causing a low cellular response causing now a inhibitory response

Explain the negative feedback mechanism

Increases force and rate of contraction

+ ionotrophic

+chromotrophic

+ dromotrophic

Beta-1 receptor actions in heart

Relaxation

Promotes potassium uptake

Activates glycogenolysis

Beta-2 receptor action in

• Respiratory, uterine, and vascular smooth muscle

• Skeletal muscle

• Human liver

When a drug bind to the beta activation, this stimulates the adenylyl cylase this causes an increase in cAMP

Two pathway:

For Positive ionotropic

• Protein kinase A → phosphorylates Ca²⁺ channels & ryanodine receptors → ↑ intracellular Ca²⁺ → Ca²⁺ binds troponin → ↑ cardiac contraction

  PKA also phosphorylates phospholamban → improves Ca²⁺ reuptake → better relaxation

For Positive chronotropic

• This will increase the activity of the sino artrial node

Explain the beta adrenergic signaling activation

Activate lipolysis

Action of B3 in Fat cell

Dilates renal blood vessels

Action of D1 in smooth muscle

Modulates transmitter release

Action of D2 in nerve endings