Neurpharm Adrenergics Flashcards
Alpha agonist examples and what is their suffix
Norepinephrine, phenylephrine, ephedrine, and epinephrine
Rinse
Norepinephrine
Catecholamine used to treat hypotension, which also has effects in treating attention disorders and depression
Phenylephrine
Drug used to treat hypotension without chronological or inotropic effects, which can also be used for rhinitis
Ephedrine
Drug which can treat urinary incontinence, and has use as a decongestant and vasopressor
Epinephrine
Catecholamine which is helpful in anaphylaxis and asthma, which is also used to increase blood pressure
How know alpha antagonists
Rine suffix
Epinephrine, norepinephrine, ephedrine, pseudoephedrine, and phenylphrine
Norepinephrine
Catecholamine a1 and a2 agonist and acts on b1
Indication for norepinephrine
Hypotension and also roles in depression and ADHD
Issue with treating hypotension with norepinephrine
Decreased renal perfusion
Phenylephrine
Selective a1 agonist that is indicated for use as a decongestant, vasopressor and mydriatic
Indication for phenylephrine
Hypotension (septic shock) and congestion
How does phenylephrine treat hypotension
Not chronological or inotropic
It increases blood pressure without effecting heart rate or contractility
How does phenylephrine treat congestion
Oral drug or ontranasal spray to treat congestion
Ephedrine
An indirect agonist which releases stored catecholamine and is categorized as a sympathomimetic.
Indications for ephedrine
Congestion (rhinitis)
Urinary incontinence
Hypotension
How does ephedrine treat congestion
Decongestant
How does ephedrine treat urinary incontinence
Vasoconstriction of the renal arteries
How does ephedrine treat hypotension
Used in surgical or obstetric procedures
Epinephrine
Catecholamine a agonist (a1 and a2) which has b1 and b2 Adrenergic activity as well
Indications for epinephrine
Anaphylaxis, asthma and hypotension
How does epinephrine treat anaphylaxis and asthma
Vasoconstriction
Asthma-b2 agonist medications are unavailable or unhelpful
How does epinephrine treat hypotension
Acts on numerous Adrenergic receptors
Increase bp in 2 ways
-increases peripheral resistance bc a receptors
-CO increased due to b Adrenergic activity
Alpha 2 agonist (sympathoplegics)
A2 agonists decreases sympathetic outflow centrally
How do a2 decrease sympathetic outflow
Treat hypertensive symptoms
Examples of a2 agonists
Condine
Alpha methyldopa
Indications for a2 agonists
Hypertension when people have
Renal disease
How do a2 agonists treat hypertension
Reduce peripheral resistance by stimulating postsynaptic a2 adrenoreceptors in CNS
Why can you use a2 agonists in hypertension in people with renal disease
Do not cause a decrease in blood flow to the kidney
Centrally acting a2 agonist
Centrally acting and decrease sympathetic outflow as they activate medullary presynaptic a2 adrenoceptors.
A2 activation __ sympathetic outflow
Decreases
Condine
Activates a receptors , which cause inhibition of norepinephrine release from synaptic vesicles.
Clondine is frequently administered with a __ and may produce side effects of __,__, and ___
Diuretic
Lethargy, dry mouth, and constipation
Adverse effect of clonidine
Severe rebound hypertension in the case of abrupt withdrawal
Alpha methyldopa
Methyldopa decreases total peripheral resistance by reducing sympathetic outflow fromt he CNS.
Indications for alpha-methyldopa
Mild hypertension and can be used together with a diuretic for increased effect.
Can alpha methyldopa be used to treat hypertension in pregnant women
Yup
Methyldopa Umayyad lead to what, causing a positive ___ test
Drug induced immune mediated hemolysis, leading to a positive direct Coombs test
Alpha methyldopa may cause SLE like syndrome with symptoms like what
Fever, pericarditis, arthralgias and malaise with positive anti nuclear antibodies
Nonselective alpha blockers
Vasodilator to Lower blood pressure by inhibiting vasoconstriction through their action at a1 while also having action at a2 receptors
Two examples of nonselective alpha blockers
Phentolamine and phenoxybenzamine
Phentolamine
Reversible drug which is useful in treating hypertensive crisis and is indicated for diagnosing pheochromocytomas
Phenoxybenzamine
Indicated for treating pheochromocytomas due to its slow onset and long duration of effects
Side effects nonselective alpha blockers
Orthostatic hypotension
Reflex tachycardia -bc leads to increased sympathetic tone
Why is phentolamine reversible
Dissociates from adrenergic receptors
Why is phentolamine ideal for the diagnosis of pheochromocytoma
Bc reversible
What crisis may we use phentolamine for
patients on MAO inhibitors who eat tyramine-containing food, in order to treat hypertensive crisis
Concaine-induced hypertensive crisis
Why is phentolamine useful for treating cocaine induced hypertensive crisis
Helpful in avoiding the unopposed alpha effects of other drugs that may be used to treat cocaine intoxication
Phenoxybenzamine
Non reversible
Used to treat pheochromocytomas and has a slower onset and longer effect than other a blockers
How does phenoxybenzamine treat pheochromocytoma better than beta blockers
Pheochromocytomas-adrenal gland
Has longer effect than other a blockers
Side effects of nonselective alpha blockers
Orthostatic hypotension
Reflex tachycardia
How do nonselective alpha blockers cause orthostatic hypotension
Inhibit a1 and a2 adrenergic receptors , they decrease vasoconstriction and vessel tone.
Why do non selective alpha blockers cause reflex tachycardia
Hypotension and added a2 inhibition are countered physiologically by increased sympathetic tone
Selective alpha 1 blockers and suffix
Osin
Block a1 in smooth muscle, arteolar and central nervous tissues
What are selective a1 blockers used to treat
Hypertension
What is tamsulsoin (a1 blocker) used to treat selectively
Urinary retention in BPH
Symptoms of selective a1 blockers
Limit ability to maintain bp
Syncope and orthostatic hypotension
Espicially in their first dose
Tamsulosin-priapism
Examples of selective a1 blockers
Osin suffix
Tamsulosin, prazosin, terazosin, doxazosin
How do selective a1 blockers work
Selectively block a1 adrenergic receptors in smooth muscle , arteriolar and CNS. Leading to vasodilation
What does tamsulosin block
A1a receptors
Where are a1a receptors
Prostate, as indicated for BPH while having little activity on hypertension
Indications for selective a1 blockers
Hypertension and BPH
Why tamsulosin good for treating BPH
Selective a1a receptors, which exist in prostate. It is helpful in treating urinary retention in BPH but has little effect on blood pressure
Treat hypertension with tamsulosin
No
Why does selective a1 blockers cause syncope
Esp prazosin
Body cant maintain cerebral blood pressure without a1 activity and this leads to syncope and dizziness
How does selective a1 blocker cause orthostatic hypotension
Body poorly controlling bp without a1 input
Patients told to stand up slowly
1st dose phenomenon
First time a patient is introduced to an a1 blocker where a sudden and severe fall in bp occurs with body position changes
Side effects of tamsulosin
Priapism
Example of selective a2 blocker
Mirtazapine
What is selective alpha 2 blocker indicated for
Depression treatment
How do selective a2 blockers work
Selectively blocking a2 receptors, and having antagonist activity at 5-HT receptors as well as other receptors
Mirtazapine
Atypical antidepressant that blocks presynaptc a2 receptors and also has serotonin 5-ht2 and 5-ht3 receptor antagonist activity
What does mirtazapine treat
Depression and other mood disorders
How does mirtazapine treat depression
Blocking a2 agonists, which in turn leads to enhanced adrenergic and serotonergic transmission
Although selective a2 adrenergic receptor is what we call mertazapine, what does it block that is clinically significant
5-HT
Side effects of mirtazapine
Sedation, weight gain, increased serum cholesterol
Why does mirtazapine cause sedation
Block of 5-HT2 and 5-HT3 receptors
How does mirtazapine cause weight gain
Potent stimulator of appetite and may cause weight gain espicially in younger patients
Why does mirtazapine cause increased serum cholesterol
Idk
What is prazosin (mini press)
Alpha blocker that selectively inhibits a1 receptors
Effects of prazosin
Relaxation and widening of blood vessels for increased blood flow and relaxes the smooth muscles in the bladder neck and prostatic capsule
Indication for prazosin
Treat hypertension and BHP and nightmares
Side effects of prazosin
Orthostatic hypertension , reflex tachycardia, inhibition of ejaculation, nasal congestion
Why should tell patient to take first does of prazosin (minipress) at night
Minimize the risk of the medications first dose effect which is severe orthostatic hypotension
How does prazosin work
Selectively block a1 receptors causing blood vessel dilation and smooth muscle relaxation of the bladder neck and prostatic capsule. Relaxing blood vessels and allows blood to flow more easily
Why does prazosin treat hypertension
A1 antagonist in walls of blood vessels, allowing the vessels to relax and widen while decreasing peripheral vascular resistance
How does prazosin treat BPH
BPH causes urinary issues
Block a1 receptors and relaxing the muscles surrounding the bladder neck (trigone and sphincter) and prostate capsule. This actions allows urine to flow more easily in patients with BPH
How does prazosin treat nightmares
Decreasing amounts of systemic adrenaline while sleeping
How does prazosin cause orthostatic hypotension
Effect ability to vasoconstriction and maintain blood pressure. Instruct patient to stand slowly and sit down if dizzy
Why does prazosin cause tachycardia
Adrenergic receptors widen blood vessels, decrease vascular resistance and lowers the hearts effort to effectively pump blood throughout the body. The decrease in blood pressure triggers the body to overcompensate by increasing the heart rate
Why does prazosin cause priapism/inhibition of ejaculation
Blocks adrenergic receptors in the prostate causing relaxed blood vessels and increased blood flow. This med affects the body ability to vasoconstrict and maintain an erection
Why does prazosin cause nasal congestion
Effects adrenergic receptors in the nasal mucosa and causes vasodilation of the nasal arterioles. Inform the patient that this drug may cause nasal congestion
First does effect of prazosin
May lose consciousness within 60 minutes so take at bedtime to minimize orthostatic hypotension and syncope
B1 agonist
Medications used because of their sympathomimetic activity
Examples of beta 1 agonists
Dobutamine
Isoproterenol
What is dobutamine used to treat
Heart failure and cardiogenic shock as it increases heart rate and contractility
What can dobutamine diagnose
Ischemic heart disease by being a pharmacological stress test agent
Why should dobutamine not be used in ischemic heart disease
It increases myocardial oxygen demand
Isoproterenol
B1 agonist which also has b2 adrenergic activity
Effects of isoproterenol
Increases cardiac inotropy, chronotropy, and dromotropy (conduction speed through AV node), which allows it to be helpful in treating bradyarrhythmias
Indication for isoproterenol
Bradyarrhythmias
Torsades de pointes (with Mg and cardiac pacing)
Isoproterenol only treat torsades de pointes which stems from ____ _ _ __
Acquired long QT syndrome
Bc of its combined b activity, isoproterenol will __ systolic bp, but _ diastolic pressure (___ ___)
Increase
Decrease (B2 vasodilation)
The b2 activity of isoproterenol allows it to be used for __ but rarely
Asthma
Dobutamine is a pure b1 agonist, and thus, acts more selectively on the __
Heart
What is dobutamine used for
Heart failure and cardiogenic shock to increase cardiac inotropy and chronotropy
Why cant dobutamine be used for ischemic heart disease
Increases myocardial oxygen demand
How can dobutamine be used in CHF
Increase contractility
Dobutamine and cardiac stress test
Help identify coronary artery disease by acting as a pharmacological stress testing agent
Isoproterenol
B1 agonist which also has action on b2 receptors
Isoproterenol increases _____ and ____ and ___
Inotropy
Chronotropy
Dromotropy
What does isoproterenol treat
Bradycardia and torsades de pointes (only when from acquired long qt syndrome)
Why can isoproterenol be used for asthma (but rarely)
B2 activity on dilation of bronchial airways
Why not use isoproterenol on ischemia
Increases myocardial oxygen demand and can worsen ischemia
How treat torsades de pointes
Isoproterenol and overdrive pacing and Mg
KEEP IN MIND that isoproterenol is only used in acquired cases of long QT syndrome which leads to torsades de pointes
What do b2 agonist do
Induce smooth muscle relaxation, bronchial dilation, vasodilation, uterine relaxation, along with insulin release
Indications for b2 agonists
Asthma, pulmonary disorders, and tocolysis
What are the short acting b 2 agonists SABA
TERBUTALINE AND ALBUTEROL
Terbutaline
Tocolytic agent and to treat asthma attacks
ALBUTEROL
Asthma attacks (and COPD exacerbations)
Long acting beta 2 agonist LABA
Salmeterol
What is salmeterol used for
Prevent the number of monthly asthma and COPD exacerbations in patients and is usually co-administered with an inhaled corticosteroid
Terbutaline
Fast acting short term treatment used for acute asthma exacerbations, and to delay premature uterine contractions (replaced ritodrine)
How does terbutaline treat asthma
Fast acting bronchodilator that works within 15 minutes with effects lasting up to 6 hours
How does terbutaline treat tocolysis
Class b not fda approved
Terbutaline and the uterus
Relaxes the uterus prior to the obstetric maneuvers used to correct uterine inversion
An important note about terbutaline is that in it __ form, it should not be used for prolonged treatment for tocolysis in preterm labor.why
Injectable
Can lead to serious maternal health problems and death
ALBUTEROL
SABA used to relieve bronchospasm in conditions such as asthma and COPD
Asthma and albuterol
Most commonly used for acute asthma attacks bc of its quick acting mechanism but can also be administered for copD.
How is albuterol administered
Inhaler or nebulized solution
What are LABA used for
Chronic conditions
Salmeterol
LAB with therapeutic effects of 12 hours
What is salmeterol used for
Severe persistent asthma (combined with corticosteroid) and used everyday to prevent the number of monthly attacks in patients
Salmeterol and asthma
Used for severe persistent asthma bc uncontrolled with SABA
COPD and salmeterol
Induces bronchial dilation. Used daily to prevent acute COPD exacerbations in patients with this condition
Selective b1 blockers
Act to block b1 receptors to treat CVD
How do selective beta blockers work
Block actions of norepinephrine and epinephrine on cardiovascular contractility, chronotropy and the body’s release of renin
Suffix of selective beta blockers
lol
Examples of selective beta blockers
Atenolol
Esmolol
Metoprolol
Some b1 blacking drugs also work as partial b agonists at high doses such as ___
Acebutolol
In general. Selective beta blockers begin with letter - and nonselective betea blockers begin with letters -. Nam two exceptions
A-m
N-z
Nonselective b blockers carvedilol and labetalol
Effects of selective b1 blockers
Decrease heart rate, contractility and renin release
Atenolol
B1 blocker
Does not cross bbb
Indications for atenolol
Arrhythmia, angina, MI and hypertension (though not first line for hypertension)
Esmolol
Very short acting drug with rapid onset. Given IV in OR
Indications for esmolol
Tachycardia and supraventricular tachycardia in OR
Also fo aortic dissection
Metoprolol
B1 blocker crosses bbb
What is metoprolol used for (selective b1 )
Control angina, MI, CHF
Migraine prophylaxis
Anxiety disorders
Partial beta agonist
B1 selective blocker also act as partial b agonist at high doses. So have some intrinsic sympathomimetic activity along with their b blocking activities
Example of partial b agonist
Acebutolol
Acebutolol
B1 blocker with partial b agonist activity at high doses
Indications for acebutolol
Arrhythmia and hypertension
Non selective beta blockers
Olol
First generation
Antagonistic effects at b1 (heart kidney) and b2 (lung peripheral blood vessels and skeletal muscle) preventing direct sympathomimetic such as norepinephrine and epinephrine from binding to these receptors
How do nonselective beta blockers work
Prevent the release of cAMP, a secondary messenger in the Gs protein signal transduction pathway. Without cAMP, PKA remains inactivated and thus Ca2+ currents are reduced
Example of nonselective b blocker
Propranolol, timolol, nadolol
Propranolol
First b blocker
Initially for angina pectoris then antihypertensive but bc of b2 blocking effects like bronchospasm and exacerbations of COPD and asthma.
Side effects propranolol
Bronchospasm, depression, exacerbation of peripheral arterial disease, masking symptoms of hypoglycemia in diabetics
What is propranolol used for now
Treatment of thyroid storm, thryotoxicosis, essential tremor, prevention of bleeding esophageal varies, akathisia and chronic migraine prophylaxis
Timolol
First line therapy for reduction of intraocular pressure in open angle glaucoma and part of empiric therapy for acute angle closure glaucoma
Timolol was initially shown to not be effective systemic hypotensive agent, however when formulated into a __ drug it was demonstrated to be extremely effective in reduction of IOP
Topical
Preferred treatment for open angle glaucoma
Topical prostaglandins
Side effects timolol
Severe bronchospasm
Nadolol
Prevention of bleeding esophageal varies. Can be used in trea,ent of migraines, ADHD, essential tremor in parkinsons
Side effects nadolol
Bradycardia, fatigue and bronchospasm
Partial B agonist
Block b receptor but also have intrinsic sympathomimetic activity and partially activate the receptor.
High doses of partial b agonist
Effects like epinephrine (increased pulse , bp, and bronchodilator)
Example of partial b agonist
Pindolol
Pindolol
B blocker that is also a partial b agonist.
Indications for pindolol
Treatment of angina pexctoris and hypertension. However, rarely done so due to its intrinsic sympathomimetic activity
Nonselective b with a blocking
Nonselectively block both b and a receptors.
A blocking effects of nonselective b blocking with a blocking
Vasodilator which potentialities the b blocking effect to reduce bp
Examples of nonselective b with a blocking
Carvedilol
Labetalol
Carvedilol
Treats CHF with ACE inhibitors and diuretics)
Labetalol
Treats pregnant induced hypertension and 2nd line in hypertensive emergencies
What CVD issues can beta blockers be used for
CHF, arrhythmia, angina, MI, hypertension and other
How do betea blockers work for CVD
Preventing normal ligands (E and NE) from binding to their adrenoceptor binding site
Heart effects of beta blockers
Decreased contractility by halting CA2+ influx by decreasing cAMP and decreasing SA and AV node conduction velocity, which also slows chronotropy.
O2 consumption is lowered as chronotropy and inotropy are decreased
By decreasing CO, bp is __
Lowered
Beta blockers have been shown to __ mortality and morbidity post MI
Decrease
Cardiac myocyte and peripheral vasculature contain _ and _ adrenoceptors which are activated by _ and _ leading to what
B1 B2
NE E
Increased inotropy, chronotropy, dromotropy (electrical conduction) and increasing bp and CO
B blockers bind to _ proteins and inhibit formation of _ to _
Gs
ATP to cAMP
What does decreased cAMP in heart cause
Decreased CA2+ currents by the sarcoplasmic reticulum of the heart …decreased heart contractility
Beta blockers _ SA and AV node conduction velocity which means they decrease dromotropy
Decrease
What are beta blockers indicated for supraventricular and ventricular tachycardia and atrial fibrillation and flutter
Bc decrease dromotropy
Why are beta blockers contraindicated in patients with heart block or AV conduction delta regardless of 1 2 or 3 degree
Decrease dromotropy
How do beta blockers decrease bp(although not first line treatment for hypertension)
- decrease chronotropy and inotropy, so heart has lower CO, contributing to lower bp andrequiring less oxygen in the process
- decrease renin secretion which reduced extracellular volume, further lowering bp and decreasing myocardial oxygen demand
Why do beta blockers decrease o2 consumption
Inhibit chronotropy and inotropic sympathetic effects
Decrease workload of heart
Decreased o2 consumption by decreasing myocardial oxygen demand
-CAN TREAT ANGINA
Why do beta blockers decrease mortality post MI
Beta blockers such as metoporlol and atenolol and bisoprolol are used after MI to decrease death and illness
What beta blockers are used in eye
Timolol and betaxolol
Reduce intraocular pressure by decreasing aqueous humor reduction
Systemic side effects of beta blockers
Respiratory-bronchoconstriction
Metabolic-decreased insulin , decrease glycolysis and lipolysis, reducing blood glucose
Diabetics and beta blockers
Aware of their blood sugar as beta blockers may mask usual signs of hypoglycemia
Why do beta blockers cause bronchocontriction
B2 receptors bronchodilator
When blocked get bronchoconstriction
B3 receptors beta blockers
Normally increase lipolysis
Beta block-decrease lipolysis
B2 beta blockers
Normally increase insulin release block if blocked
Beta blockers glycolysis
Block it
Glycogenolysis decreased
Beta blockers and eye
Ciliary epithelium contains beta adrenergic receptors and ligand binding (e and NE) stimulated the formation of aqueous humor. Thus beta blockers decrease queues humor formation
How do timolol and betaxolol decrease aqueous humor formation
Block beta receptors on ciliary bodies
Epinephrine
Direct sympathomimetic that is used for treatment of hypotension , anaphylaxis and open angle glaucoma.
Administration of epinephrine
IV
Epinephrine is metabolized by the ___ prior to excretion
Liver
Effects of epinephrine
Increase heart rate and systolic bp and acute on a and b receptors
Epinephrine is an a and b __
Agonist
Epinephrine effect on a1
Constrict smooth muscle of resistance blood vessels, such as those in the skin and splanchnic needs, causing increased peripheral resistance and venous return
Epinephrine on b1 and b2
Increase heart rate and contractility
Increases lipolysis and renin release while causing vasodilation also increase uterine tone
Indications for epinephrine treatment
Hypotension
Anaphylaxis
Allergy
Glaucoma
How does epinephrine treat hypotension
Increases systolic pressure as a result of positive inotropic and chronotropy effects on the heart.
High doses of epinephrine
Vasoconstriction within skeletal muscle vasculature
How does epinephrine treat anaphylaxis (asthma attack and anaphylactic shock)
Vasoconstrict I’ve and reversing angioedema and hypotension
Stimulation of b2 causes bronchodilator as well as increasing intracellular cyclic adenosine and monophosphate production in mast cells and basophils, reducing release of inflammatory mediators
How does epinephrine treat allergy
Patients with allergies undergoing immunotherapy may be administered epinephrine to reduce possible immune response to the allergen
How does epinephrine treat glaucoma
Act on eye is less selective alpha agonist and decreases aqueous humor production through vasoconstriction of ciliary body blood vessels. This decreases ocular pressure in open angle glaucoma
What should we not use epinephrine for
Cloaked angle glaucoma
Ephedrine
Indirect sympathomimetic that works to release stored catecholamine such as NE from sympathetic neurons
Ephedrine is a _ and _ agonist
A and b
Indication for ephedrine
Rhinitis
Hypotension
Urinary incontinence
Ephedrine as an a agonist
Release stored catecholamine as an indirect agonist
Constrict smooth muscle of resistance bv such as those in the skin and splanchnic beds causing increased peripheral resistance and venous return
Ephedrine as a b agonist
B1 and b2 and increases Herat rate and contractility
Increases lipolysis and renin release while causing vasodilation
Decrease uterine tone
Ciliary muscle relaxation and increase aqueous humor production
Ephedrine and rhinitis
Yup
Ephedrine and hypotension
A1 agonist effect of increased bp
Ephedrine and urinary incontinence
Constrict urinary sphincters and vasoconstrict renal arteries
Norepinephrine
Catecholamine and direct sympathomimetic
Indications for NE
Hypotension
Depression and attention disorders
Side effects NE
Decreased renal perfusion
NE is an a and b __
Agonist
NE as an a agonist
A1 and a2
NE as a b agonist
B1 agonist increased heart rate , contractility , and renin release
Little activity on B2
NE and hypotension (emergencies such as neurogenic or septic shock)
Raise diastolic bp and total peripheral resistance more so than E due to its vasoconstrictor activity and lack of effect on B2 receptors in skeletal muscle vascular bed.
Why does NE decrease renal blood flow
Idk but get impaired kidney function
Phenylephrine
Direct sympathomimetic drug which acts as an a1 agonist
Indications for phenylephrine
Rhinitis and emergency hypotension
Ocular procedures 9mydrasis)
Who should we not use phenylephrine in
Patients with narrow angle glaucoma
Phenylephrine as an a1 agonist
Constrict smooth muscle of resistance blood vessels such as those in the skin and splanchnic beds causing increased peripheral resistance and venous return
Phenylephrine and a2
Agonist
Phenylephrine and mydratic
Dilates pupil (in conjunction with anticholinergic) and should be avoided in patients with narrow angle glaucoma
Phenylephrine and rhinitis and hay fever
Most commonly prescribed OTC decongestant
Also open obstructed eustsachian tubes
Phenylephrine and hypotension
Short term emergencies increasing mean blood pressure with no effect on pulse pressure. 9severe hemorrhage where there is inadequate perfusion of the heart and Brian)
Phenylephrine caused __ chronotropy and __ inotropy
Decreased increased
Why does phenylephrine cause increas chronotropy but increased inotropy
Increases systemic vascular resistance, it can induce a barre pet or mediated vagal response against the heart, resulting in a slower heart rate(aka bradycardia). It also directly stimulates alpha receptors on cardiacmyocytes causing them to contract harder or increasing inotropy
