an2

ANS 2

for Pupillary opening which muscles does symp and parasymp innervate

Sympathetic
Radial muscle of iris

Circular muscle of iris

what about for lens focusing

Parasympathetic
Ciliary muscle

what affects does sypathetic have on vascular smooth muscle

Vascular smooth muscle
– Sympathetic
• Skin, splanchnic vessels Contraction (α1)
• vessels in skeletal muscle Relaxation (Muscarinic)

what receptor does NE stimulate

NE mainly stimulates 1 receptors (in vessels)
• increase blood pressure markedly

what does Epinephrine have higher affinity for?

E has higher affinity for B receptor (in cardiac muscle)
• increase heart rate and contractility
• Less effect on mean arterial pressure

Effect of sym and parasym on:
GI smooth muscle

what does denervation supersensitivity mean?

If an organ loses its nerve supply, it becomes extra sensitive to the neurotransmitter that nerve normally releases.

how many adrenergic receptors and which have affinity for E and NE

a1, a2, b1, b2

• all respond to NE and E

• • NE: a > b
  • E: b > a

functions of Alpha1

function of A2

Inhibits NT release, thus inhibiting
sympathetic (adrenergic) activation

a2 isnt exactly opposite of a1 why is that

what drugs (secondary messengers) does adrenergic receptors use

what are major effects of β2

smooth muscle RELAXATION

β2 generally causes smooth muscle relaxation.

Major effects:

Bronchi → dilation

Blood vessels → dilation

Uterus → relaxation

It also promotes:

glycogenolysis and glucagon release.

what are Adrenergic agonists

sympathomimetics They mimic actions of:

norepinephrine, epinephrine and dopamine.

They're useful when you WANT sympathetic-type effects

function of epinephrine

non-selective adrenergic agonist

“Non-selective” means it activates both α and β receptors, rather than targeting only one.

effects of epinephrine on a1,b1,b2 receptors

• α1 → vasoconstriction → ↑ blood pressure

• β1 → stimulates heart → ↑ heart rate and contractility

• β2 → bronchodilation → opens the airways

why is epinephrne used along side anesthetic

Epinephrine → α1 → vasoconstriction around injection site → ↓ blood flow → anesthetic stays in the area longer

what does Cocaine do?

Inhibits the reuptake of serotonin, norepinephrine, and dopamine. Non- selective for receptor subtype and organ.

Cocaine → blocks reuptake → ↑ NE, dopamine & serotonin in synapse → stronger/longer signaling

side effects of cocaine

The increased NE also stimulates the sympathetic system outside the brain, explaining the slide's effects such as ↑ heart rate, sweating, and ↑ blood pressure.

effects of Amphetamines

1. ↓ uptake/reuptake of neurotransmitters
2. ↑ release of neurotransmitters

what does MAO do?

enzyme monoamine oxidase (MAO) helps break down monoamine neurotransmitters. So if you inhibit MAO, less neurotransmitter is broken down → its levels/effects increase.

how is MAO used in parkinsons

Parkinson's involves reduced dopamine signaling in the brain.

Selegiline inhibits MAO → ↓ dopamine breakdown → ↑/prolongs dopamine

That's why the slide says it can be used with levodopa:

Levodopa → ↑ dopamine production
Selegiline → ↓ dopamine breakdown

→ Together, they help maintain dopamine signaling.

how do antidepressant work

Phenelzine → inhibits MAO → less monoamine breakdown → increased/prolonged monoamine neurotransmitter effects

what does a1 activation cause

what does Beta 1 activation cause

what do b2 receptors do

Main points to remember about the 3 receptors

explain the diff generation of A and B receptor blockers

1. 1st generation- Non selective (B1 and B2)

2. 2nd generation- Cardioselective (B1)

3. 3rd generation- Partially selective (with A1 inhibition)