Exam 1 - Autonomic Nervous System Flashcards
Peripheral Nervous System (PNS) Adrenergic Target Organs - Dopamine
- Kidney - Dilation of kidney vasculature (used for shock)
- Is considered adrenergic but does not respond to epi and NE and is primarily found in the CNS
- Used for shock and hypotension
Define Catecholamines. Give examples
- Can’t cross BBB
- Short duration of action
- Cannot give by mouth (PO)
- EX: epi, NE, dopamine, dobutamine, isoproterenol
What receptors does Norepinephrine act on?
adrenergic rec’s alpha 1 & 2 and beta 1
Therapeutic uses of Dopamine?
shock
heart failure
acute renal failure
Norepinephrine does not activate which receptor??
Beta2
Synthetic drug that selectively stimulates B1 receptors, especially in the heart
Dobutamine
Define Agonist
directly activate receptor
Post-ganglionic neurons of the PSNS and SNS releases what NT(s)?
PSNS: ACh
SNS: NE, Epi, Dopamine
What are some key things that epinephrine is used to do?
delay absorption of local anesthetic
control superficial bleeding
mydriasis during ophthalmologic procedures
restore cardiac function in arrest
bronchial dilation in asthma
Selective direct-acting sympathomimetic druggs (adrenergic receptor agonists)
Phenylephrine (A1)
Dobutamine (B1)
Terbutaline (B2)
Define Sympatholytic. Give alternate names
antiadrenergic
Parasympathomimetic, Cholinergic-like,
Synthetic drugs that is non-selective for B1 and B2
Isoproterenol
Afferent transmission
sensory neurons, impulses toward the spinal cord & brain
Adverse effects of Epinephrine?
hypertensive crisis
dysrhythmias
angina pectoris
necrosis following extravasation
hyperglycemia
Phenylephrine activates alpha1 receptors. What therapeutic uses does this drug have?
reduce nasal congestion
elevate blood pressure
dilate pupils
Indirect acting
Stimulate release of neurotransmitter
Direct acting
Stimulate receptor
Define Parasympatholytics. Give alternate names
anticholinergic
Sympathomimetic, adrenergic-like, muscarinic antagonist
What receptors does ACh act on?
Preganglion: both PSNS and SNS Nicotinic M receptor
Postganglionic: PSNS Muscarinc and Nicotinic receptor and sweat gland for muscarinic receptor in SNS
Define Sympathomimetic. Give alternate names
adrenergic (SNS)
parasympatholytics, anti-cholinergic-like
Pre-ganglionic neurons of the PSNS and SNS releases what NT(s)?
ACh
Describe exocytosis
- APs travels down axon to synaptic knob
- Large influx of Ca++
- Release of NT or catecholamines (ACh, Epi, NE, or Dopamine) into the synapse
What receptors does Dopamine act on?
alpha 1, beta 1 and dopamine receptors
Synthetic drug used to cause vasoconstriction; selective for A1 receptors
Phenylephrine
What receptors does Epinephrine act on? Where is it released?
alpha 1 & 2 & beta 1 & 2
Adrenal medulla
What is the choice of treatment for anaphylactic shock?
epinephrine
Define Parasympathomimetic. Give alternate names
Cholinergic (PSNS)
Sympatholytic, antiadrenergic-like, muscarinic agonist
Adverse Effects of Muscarinic Antagonist
- Xerostomia (Dry mouth)
- Blurred vision and photophobia
- Elevation of intraocular pressure
- Constipation
- Anhidrosis (deficiency of sweat)
- Tachycardia
Define Antagonist. Give examples
prevent receptor activation
examples: naloxone, antihistamines, beta blockers
Efferent transmission
motor neurons, impulses away from the spinal cord, brain & glandular tissue
Drugs that don’t directly interact with the receptors, but increase the amount of norepinephrine available to stimulate adrenergic receptors
Indirect acting sympathomimetic drugs
Compare SNS to PSNS Effects on:
Cardiac Output/Heart Rate
Vascular Tone
Respiration
GI
Secretions
Eye
Sex
Uterine SM
Prostate
Describe the Alpha 2 receptor
Autoregulation receptor. Has no target organ to activate. Activated by NE or Epi only
What are clinical consequences of dopamine receptor activation?
dilation of the vasculature of the kidneys
Peripheral Nervous System (PNS) Adrenergic Target Organs - Alpha 1 Receptor
- Eye - Contraction of radial & sphincter muscle & inc. pupil size
- Arterioles - Constriction of arterioles (skin, viscera mucous membrane)
- Veins - Venous constriction
- Sex organ - Male ejaculation
- Prostate - Contraction of prostate
- Bladder - Contraction of trigone & sphincter muscle in bladder
Peripheral Nervous System (PNS) Cholinergic Target Organs
- Eye - Contraction of ciliary muscle for near vision & Miosis (dec pupil diameter) – pinpoint pupils
- Heart – Dec heart rate, hypOtension
- Blood Vessels – Vasodilation (lower BP!)
- Lung – Contraction of bronchi (difficulty breathing)
- Bladder - Contraction of detrusor & relaxation of trigone & sphincter muscle (causes urination) (increased urination!!!)
- GI Tract - Salivation, inc gastric secretions & intestinal tone & motility, defecation
- Sweat glands - sweating is a SNS response but is through activation of muscarinic rec by ACh
- Sex organs – Erection (due to dilation of blood vessels) this is only spot where the SNS and PSNS work together (PSNS/erection & SNS/ejaculation)
Terbutaline activates Beta2 receptors. Therefore this drug’s therapeutic uses are….
asthma
delay of preterm labor
Define Noncatecholamines. Give examples
- Crosses BBB
- Longer duration of action
- Can give PO
- EX: Phenylephrine, ephedrine, terbutaline
Peripheral Nervous System (PNS) Adrenergic Target Organs - Beta 2 Receptor
- Arterioles - Dilation of arterioles in heart, lung & skeletal muscle
- Lungs - Dilation of the bronchi in the lungs
- Uterus - Relaxation of the uterus
- Liver - Glycogenolysis in the liver
- Skeletal muscle - Enhanced contraction of skeletal muscle & glycogenolysis
Non-selective direct acting sympathomimetic drugs (adrenergic receptor agonists)
Epinephrine (all receptors)
Norepinephrine (except B2)
Isoproterenol (B1 and B2)
Peripheral Nervous System (PNS) Adrenergic Target Organs - Beta 1 Receptor
- Heart - Inc HR, force of contraction, AV conduction velocity
- Kidney - Renin release
