Chapter 18/19 Flashcards
Alpha 1 Adrenergic Function
- Increase cardiac contractility and vasoconstriction
- Dilate Pupils, decrease salivary gland secretion
- Increase bladder and prostate contraction
Alpha 2 Adrenergic Function
- Inhibit norepinephrine release
- Decrease GI motility and tone
Beta 1 Adrenergic Function
- Increase Cardiac contractility
- Increase renin secretion
Beta 2 Adrenergic function
- Decreases GI tone and motility
- Activates liver glycogenolysis
- Bronchodilation
- Increases blood flow in skeletal muscles
- decreases uterine tone
Inactivation of Neurotransmitters
- reuptake of the transmitter back into the neuron
- enzymatic transformation or degradation
- diffusion away from the receptor
2 Enzymes that inactivate the metabolism of norepinephrine
- Monoamine oxidase (MAO)
2. Catechol-O-methyltransferase (COMT)
How do drugs stop the termination of the neurotransmitter?
- By inhibiting the norepinephrine reuptake, which prolongs the action of the transmitters
- inhibiting the degradation of norepinephrine by enzyme action
Adrenergic agonists
sympathomimetics or adrenomimetics
adrenergic blockers
sympatholytics or adrenolytics
Where are adrenergic receptor sites?
cells of muscles such as heart, bronchiole walls, GI tract, urinary bladder, and ciliary muscle
Categories of sympathomimetics
- direct-acting (directly stimulate: epinephrine/norepinephrine)
- indirect-acting (stimulate the release of norepinephrine from terminal nerve endings: amphetamine)
- mixed-acting (both direct and direct which stimulate the adrenergic receptor sites and stimulate release of norepinephrine from terminal nerve endings: ephedrine)
Epinephrine
- Nonselective
- Action: Alpha 1, Beta 1 and 2
- Contraindications: dysrhythmias, cerebral arteriosclerosis, pregnancy, narrow angle-glaucoma, cardiogenic shock.
- PK: subq/im/iv
- Quick onset–> lasts 1 to 3 hrs
- Action: inotropic, vasoconstrictor, bronchodilator
Albuterol
Selective: B2 adrenergic
- treat bronchospasm, asthma, bronchitis, COPD
- Side effects: tremors, dizziness, hallucinations, cardia dysrhythmias
- Increase effect with other sympathomimetics,MAO inhib, TCAs
Adrenergic blockers OR sympatholytics
- Block by occupying receptors (Directly)
- By inhibiting the release of norep/epi (indirectly)
Alpha-Adrenergic blockers
- Selective: block A1
- Nonselective: block A1/A2
Alpha-Adrenergic blocker function
-vasodilation
-decrease BP
-Reflex tachycardia
-Decrease symptoms of BPH and PVD
(cardura, regitine, minipress, hytrin)
Beta-Adrenergic Blockers
- Block beta 1: decrease BP and P
- Block beta 2: uterine contraction, bronchoconstriction
Non-selective Beta-Adrenergic
Inderal
- used for angina, cardiac dysrhythmias, hypertension, heart failure
- Side effects: weight gain, impotence, decreased libido, alopecia
Selective beta-adrenergic blocker
metopropol, atenolol
-side effects: bradycardia, hypotension, dysrhythmias, headaches, dizziness, fainting, fatigue, mental depression, nausea, vomiting, diarrhea, blood dyscrasias, hypoglycemia
Adrenergic neuron blockers
Drugs that block the release of norepinephrine from sympathetic terminal neurons
-used to decrease blood pressure
(reserpine, guanethinidine, guanadrel)
Cholinergics/ Parasympathomimetics
mimic acetylcholine
Cholinergic Receptors
- muscarinic: stimulate smooth muscle and slow heart rate
2. nicotinic receptors: affect skeletal muscles
Cholinergic Agonists
- Direct: act on the receptors to activate tissue response
2. indirect: inhibit acetylcholinesterase
Cholinergic action in cardiovascular
decrease P and BP, vasodilation, slows conduction of AV node
Cholinergic action in GI
increase tone and motility, increase peristalsis, relax sphincter muscles
Cholinergic action in GU
contract bladder, increase ureter tone, relax sphincter muscles, stimulate urination
Cholinergic action in eye
pupil constriction, increase accomodation
Cholinergic action in lungs
bronchial constriction, increase secretions
Cholinergic action in striated muscle
increase neuromuscular transmission
Direct acting cholinergics
selective to muscarinic receptors
- located in smooth muscles
- Side effects: hypotension, bradycardia, blurred vision, miosis, excessive salivation, sweating, increased gastric acid, nausea, vomiting, diarrhea, bronchoconstriction
Indirect acting cholinergics
- function: break down cholinesterase enxyme into choline and acetic acid
- function: allow ach to activate receptors
- Effects: stimulate skeletal muscles, increase tone, GI motility, bradycardia, bronchial constriction
Antiocholinergics
- heart: large doses increase P, small decrease P
- lungs: bronchodilation, decrease secretions
- GI: relax smooth muscle tone, decrease peristalsis, decrease secretions
- GU: relax destrusor muscle, increase sphincter constriction
- Eye: dilate pupils, decrease accomodation
- Glands: decrease salivation, perspiration
- CNS: Decrease tremors and rigidity
Alpha 1 Receptor
- Vascular smooth muscle
- vasoconstriction
Alpha 2 Receptor
Adrenergic and cholinergic nerve terminals
-decrease neurotransmitter release
Beta 1 receptor
heart
increase in rate and force of contraction
Beta 2 receptor
Broncial smooth muscle
Bronchodilation
