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Pharmacology
Exam 2
85
Veterinary Medicine
Graduate
02/09/2011

Additional Veterinary Medicine Flashcards

 


 

Cards

Term
What is the major difference in signal transmission between the Somatic nervous system and the Autonomic nervous system? 
Definition

The somatic nerves synapse from CNS somatic neurons to skeletal muscles.

 

The autonomic nerves synapse from CNS preganglionic neurons to postganglionic effector neurons and then to effector organs.  

Term
What is the origin of preganglionic fibers of the sympathetic nervous system?
Definition

Pre-ganglionic fibers of the sympathetic nervous system originate in cell bodies in the thoracic and lumbar regions of the spinal cord. 

 

Then they enter the paravertbral chain of cympathetic ganglia. 

Term
What is the size and innervation of post ganglionic fibers of the sympathetic nervous system?
Definition

Post ganglionic fibers of the sympathetic nervous system tend to be long and often have multiple innervations. 


Term
What is the origin of preganglionic parasympathetic nervous fibers?
Definition

Preganglionic nerves of the parasympathetic nervous system originate from cell bodies in the midbrain, medulla oblongata, or sacral region of the spinal cord. 

 

Then they enter ganglia near to the innervated structure. 

 

Term
What is the size and innervation of post ganglionic parasympathetic nerve fibers?
Definition

Post ganglionic parasympathic nerve fibers tend to be short because they coming from ganglia in or near target organ. 

They tend to have singular innervations of these nearby target organs. 

Term
What is the general function of the sympathetic nervous on the heart and GI?
Definition

Heart : excitation 

GI : inhibition

 

This is the fight or flight response and is typically associated with the emergency response = getting more blood pumped and decreasing functions like digestion. 

Term
What is the general function of the parasympathetic nervous system on heart and GI?
Definition

Heart : inhibiton 

GI : excitation 

Term
What is the sympathetic mediated response of beta-1 receptors and where are they found?
Definition

Beta 1 receptors are present on the heart: SA node, ventricles, AV nodes 

 

Norephinephrine released from postganglion fibers onto these cells increase heart rate, contractivity and conduction.

Term

 

What is the sympathetic mediated response of beta-2 receptors and where are they found?

 

Definition

Beta-2 receptors are found:

- bronchioles smooth muscle causing dilation of airways

-vasculature of organs/muscle causing vasodilation

 

Postganglionic fibers release norepinephrine onto these cells and cause dilation. 

Term

 

What is the sympathetic mediated response of alpha-1 receptors and where are they found?

 

Definition

Alpha-1 receptors are found in vascular smooth muscle 

 

When norepinephrine is released onto these receptors it causes peripheral vasoconstriction

Term

 

What is the sympathetic mediated response of alpha-2 receptors and where are they found?

 

Definition

Alpha-2 receptors are found on the terminal end of post ganglionic adrenergic fibers releasing epinephrine - producing auto-inhibition of NE. 

 

Also present on vasculature causing vasocontriction.

Term
What are the 5 CATECHOLIMINE adrenergic drugs?
Definition

Epinephrine 

Norephinephrine 

Isoproteronol

Dopamine 

Dobutamine 

Term
What neurotransmitter do sympathetic preganglionic neurons release, and onto what type of receptors? 
Definition
Sympathetic PREganglionic neurons release ACh onto Nicotinic receptors of postganglionic neurons (or adrenal medulla) 
Term
What neurotransmitter is released from sympathetic postganglionic neurons, and onto what type of receptors?
Definition
Sympathetic POSTganglionic neurons release Norepinephrine onto adrenergic receptors in effector tissues. 
Term
What neurotransmitter is released from parasympathetic Preganglionic neurons, and onto what receptors?
Definition
Parasympathetic PREganglionic neurons release ACh onto Nicotinic receptors of postganglionic fibers. 
Term
What neurotransmitter is released from parasympathetic postganglionic neurons, and onto what receptors?
Definition
Parasympathetic POSTganglionic neurons release ACh onto Muscarinic receptors of effector cells.  
Term
What are the types of cholingeric receptors?
Definition

Muscarinic (M1-M5 subtypes) 

Nicotinic (Nm and Nn subtypes) 

Term

What are the subtypes of Muscarinic cholinergic receptors?

Where are they found?

Definition

M1 - Receptors in neurons to mediate excititory postsynaptic potential 

M2 - Receptors found in heart to decrease excitibility

M3 - Receptors in smooth muscles, sphincters, and secretory glands

M4 - Receptors found in CNS

M5 - Receptors found in midbrain dopaminergic neurons to increase dopamine release 

Term

What are the subtypes of Nictotinic cholingeric receptors?

Where are they found?

 

Definition

Nm - Receptors are found in muscle of neuromuscular junctions

Nn - Receptors are found in the neurons of the CNS and autonomic ganglia 

Term
The effect of what neurotransmitter(s) is/are mediated by Cholinergic receptors?
Definition

Acetylcholine 

Muscarinic and nicotinic receptors take in acetylcholine and regulate a response. 

Term
The effect of what neurotransmitter(s) is/are mediated by Adrenergic receptors?
Definition

Norepinephrine & Epinephrine

alpha 1,2 and Beta 1,2 receptors take in these drugs and mediate a response. 

Term
What are the types of Adrenergic receptors?
Definition

Alpha 1, 2 

Beta 1, 2

Term
Where are alpha-2 receptors and what is their effect?
Definition

Vessels of heart, kidneys - constriction 

Bronchial glands, intestine, kidney (renin), pancreas (acini and islets cells) - - Decreased secretion 

GI - decreased motility and tone 

fat cells - decreased lipolysis 

 

vascular vasoconstriction, decreased secretion

Term
Where are Beta-1 receptors and what is their effect?
Definition

The heart primarily 

SA node, AV node, ventricles - resulting in INCREASED contractility and conductivity. 

Term
Where are Beta-2 receptors and what is their effect?
Definition
Term

If your co-worker accidentally stabbed you in the finger with a needle containing epinephrine - what drug would you administer to counteracts its effects? 

(ie. How do you keep your finger alive?)

Definition

You would use Phentolamine

(an alpha 1 adrenergic antagonist) 

 

This would prevent the alpha 1 receptors of the periphery from extreme vasocontriction that would occlude the blood supply to the finger 

 

Or you could let your finger fall off and sue them...

Term
What drug acts as a potent agonist to all adrenergic receptors?
Definition
Epinephrine 
Term
What drugs are agonists to Alpha 1 receptors ?
Definition

Epinephrine 

Norepinephrine 

Phenylephrine 

Term
Which neurotransmitter released from the adrenal gland is more readily susceptible to degradation?
Definition

Norepinephrine 

 

Because of this - it is less available in circulation 

Term
What are the agonists to alpha 2 receptors? 
Definition

Epinephrine 

Norephinephrine

Medetomidine 

Xylazine 

Term

What are the agonists to Beta 1 receptors? 

 

Definition

Epinephrine 

Norepinephrine 

Isoproterenol

Dobutamine 

Term

What are the agonists to Beta 2 receptors? 

 

Definition

Epinephrine 

Ractopamine 

Isoproterenol 

Terbutaline 

Term

What are the antagonists to alpha 1 receptors?

 

Definition

Phenoxybenzamine

Prazosin

Phentolamine 

Term
What are the antagonists to Alpha 2 receptors? 
Definition

Phentolamine 

atipamezole 

yohimbine

Term
What are the antagonists to Beta 1 receptors?
Definition

Atenolol

Propranolol

Term
What are the antagonists to Beta 2 receptors?
Definition
Propranolol
Term
Which neurotransmittor is commonly used to treat acute renal failure?
Definition

Dopamine 

At high doses its a beta agonist - stimulating beta 1 receptors on the kidney evoking vasodilation - 

provides the kidneys with better perfusion. 

Term
Why is epinephrine used to treat cardiac arrest 
Definition

Although epinephrine is an agonist to all adrenergic receptors, there are more Beta 2 receptors present in the heart and have the predominant effect. 

Thus, it causes increased contractility, increased HR, and increased CO.  

Term
What are the common clinical uses for epinephrine?
Definition

Local anesthetic - peripheral vasocontriction 

Cardiac arrest/ AV block - increased HR, BP, CO

 

Term
What are the clinical uses for Ephidrine? Why?
Definition

Urinary incontinence

This is because it is an beta 2 agonist which initiates the release of NE. 

 And THAT stimulates the alpha receptors on the urinary sphincter, causing it to contract and have better control at retaining urine.

 

Term
What are the clinical uses for Dobutamine?
Definition

Short term treatment of heart failure 

This is because it is a beta-1 agonist which are present in high quantity on the heart and will increase cardiac output. 

Term
Why would ephedrine be used as a dietary supplement?
Definition

Because ephedrine is a beta 2 agonist - its stimulates the release of NE, 

It creates a generalized stimulant - this was banned for athletes. 

(and can be made into illegal drugs...) 

Term
What are the clinical uses of phenylephrine? why?
Definition

Pupil dilation 

This is because it is an alpha 1 agonist causing constriction of the muscles of the eye, including the iris.  

OTC decongestant

as an alpha 1 agonist it constricts the peripheral vasculature and promotes decongestive activity. 

Term
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Definition
Because it is an alpha 1 agonist thus causing peripheral vasoconstriction and promoting decongestive activity.
Term
What are the clinical uses of albuterol? Why?
Definition

Used in asthma and crisis of airway constriction.  

Albuterol is a beta 2 agonist and will thus cause bronchodilation.  

 

Must be administered through inhalation because it has a high pKa and will be in ionized form in the blood and absorption is low. (ie. shouldnt be given orally)

Term
What are the clinical uses of Clenbuterol? Why? 
Definition

Clenbuterol is used to treat Chronic obstructive pulmonary disease (horses and humans) because it is a beta 2 agonist, causing bronchodilation.  Can be administered orally, stays in the system for a long time. 

 

 

Term
Why is it illegal to use Clenbuterol in horses? 
Definition

It is illegal because people MISUSED the drug for its side effect as a repartitioning agent.  

MEANING - The beta 2 receptors on skeletal muscle are activiated and cause and increase in glycolysis - resulting in lean muscle mass.  

 

Withdrawl time is also very high. 

Term
What are the clinical uses of Terbutaline? Why? 
Definition

Since terbutaline is a beta 2 agonist is can be used to treat asthma (in cats & horses) because it is a bronchodilator. 

It has a very short acting (30 minutes) 

Term
What are the clinical uses of propanolol? Why?
Definition
It is a Beta (1 & 2) antagonist and it is primarily used to treat situations of increased blood pressure and tachycardia.  It competes primarily with the beta receptors of the heart, causing decreased contraction, cardiac output and conduction.  
Term
What are the clinical uses of Atenolol? Why?
Definition

Atenolol is used to decrease heartrate because it is a beta 1 receptor antagonist. In situations where there is tachycardia or hypertension (superventricular arrhythmias, hypertrophic cardimyopathy) it is used to decrease heart rate, contractility, and cardiac output.  

 

Also is being used as an anti-anxiety drug - decreased heart rate during an attack lessens the effect. 

Term
What are the clinical uses of Phenoxybenzamine? Why? 
Definition

Phenoxybenzamine is a ALPHA 1 Antagonist

Laminitis (horses)

Blocks alpha 1 receptors that would cause vasoconstriction resulting in decreased peripheral resistance.  

Inappropriate Urine Retention (cat and dog)

Blocks alpha 1 receptors on the urinary sphincter that would normally promote constriction, thus reducing the sphincter tone. 

Term
What are the clinical uses of Phentolamine? Why? 
Definition

Overcome peripheral vasocontriction from increased epinephrine - ALPHA 1,2 blocker

 

This can be used if accidental dose of epinephrine given, or if there is an epinephrine secreting pheochromocytoma (tumor).  

Term
What are the clinical uses of Prazosin? Why? 
Definition

ALPHA 1 Antagonist

 

Used in Preanesthetic agent because it blocks the alpha 1 receptors and allows for and sedative effect while causing vascular smooth muscle to relax. 

Term
Where would you find Nicotinic receptors?
Definition

On both parasympathetic and sympathetic postganglionic neurons that have ACh secreted onto them, 

(and on the skeletal muscle of the somatic nervous system) 

Term
What is a Cholinomimetic drug?
Definition

Drugs that produce ACh-like effects.  

 

 

Term
What is a Parasympathomimetic drug?
Definition

Drugs that produce ACh-like effects at parasympathetic neuro-effector junctions. (This would be at the site of a ACh releasing Postganglionic neuron onto the muscarinic receptor of an effector cell.)

 

 

These drugs are generally inhibitory to the heart, and cause SECRETION (of all kinds), increased gut motility

Increased secretion, sweat, saliva, feces, urine, the works...

 

Term
What are Direct-Acting Parasympathomimetic drugs?
Definition

Agonists to the muscarinic ACh receptor (on the effector cell that is of a postganglionic parasympathetic neuron releasing ACh)

 

Acetylcholine (highly susceptible to degradation) 

Methacholine

Carbachol (Carbamylcholine) 

Term
What are cholinesterase inhibiting parasympathomimetics? 
Definition
These are drugs that block the acetylcholinesterase that degrade endogenous ACh ( between postganglionic parasympathetic neurons and the muscarinic receptor of its effector cell) 
Term
What are Parasympatholytics?
Definition
Drugs that block or inhibit ACh-like effects at parasympathetic neuro-effector junctions. 
Term
What are the clinical uses for Bethanechol? Why? 
Definition
Bethanechol is used for Stimulating the GI tract of horses.  Because it acts on muscarinic receptors it causes an increase in parasympathetic drive, which increases gut motility (at many levels) and salivation (secretions).  
Term
What are the clinical uses for Pilocarpine? Why? 
Definition

Pilocarpine is used to treat GLAUCOMA,  

It decreases the intraocular pressure by constricting the iris and causing miosis.  

 

KCS (keraconjunctivitis sicca - DRY EYE) - - causes increased secretions of the lacrimal gland by stimulating the muscarinic receptors. 

Term
What are some adverse effect of parasympathomimetics?
Definition

- slowing of the heart rate (stops heart beat = bad)

- Increased airway resistance (from increased secretions and bronchoconstriction as stimulated by parasympathetic)

- Hypotension ("SLUD" syndrome - from secretory, smooth muscle and sphincter effects)  

AT HIGH CONCENTRATIONS:

Nicotinic effects -> stimulation of sympathetic ganglia -> catecholamine released from adrenal -> muscle fasiculations

Term
Where are most M1 receptors found? 
Definition
In the GI tract
Term
Where are most M2 receptors found?
Definition
The HEART
Term
Where are most M3 receptors found?
Definition

Smooth muscle and everywhere else

(eye, bronchial smooth muscle, urinary bladder, GI sphincters)

Term
What is the agonist of all cholinergic receptors?
Definition
Acetylcholine!
Term
What are the agonists to muscarinic receptors?
Definition

Acetylcholine

Bethanechol

Term
What are the antagonists to muscarinic receptors?
Definition
Atropine only!!
Term
What are the agonists to NM receptors?
Definition

Acetylcholine 

Nicotine

Succinylcholine

 

Term
What are the antagonists to NM receptors?
Definition
Tubocurarine
Term
What are the agonists of NN receptors?
Definition

Acetylcholine

Nicotine

 

Term
What are the antagonists to NN receptors?
Definition
Hexamethonium 
Term

Alpha1 receptors are assocaited with which of the following effects:

A) Cardiacceleration

B) Vasodilation 

C) Pupillary Dilation 

D) Bronchodilation 

E) Pupillary Constriction 

Definition

Answer: C) Pupillary dilation 

By causing the IRIS to CONSTRICT it causes the pupil to dilate (Mydriasis)

 

A) would be Beta 1 receptors

B) would be Beta 2 receptors

D) would be Beta 2 receptors 

E) is associated with muscarinic cholinergic receptors (parasympathetic) 

Term

What is the most likely cause of death in organophosphate poisoning?

A) GI Bleeding

B) Hypertension

C) Respiratory Failure 

D) Congestive Heart Failure

E) Cardiac Arrhythmia

 

Definition

Answer: D) Respiratory failure. 

 

Organophosphate cholinesterase inhibitors prevent the hydrolysis of ACh, so ACh accumulates at synapses, evokes bronchoconstriction and secretion (parasympathetic).  Also causes paralysis of respiratory muscles (diaphragm) = Respiratory failure

Term

Which of the following adrenergic agonists at clinical dose produces dilation of vessels in muscle, constriction of cutaneous vessels, and positive inotropic effects on the heart (increased contraction)?

A) Phenylopropanolamine

B) Isoproterenol

C) Isoxsuprine 

D) Epinephrine

E) Dobutamine 

Definition

Answer: D) Epinephrine - 

Agonist of alpha 1 receptors causing peripheral vasoconstriction, agonist of Beta 1 causing increased heart contractility and Beta 2 agonist causing muscle vasodilation. 

ACTIVATES ALPHA 1, BETA 1, BETA 2!!

A) phenylopropanolamine - alpha 1 agonist only 

B) Isoproterenol - Beta 1,2 agonist but NOT Alpha 1

C) Isoxsuprine - Beta 2 agonist only 

E) Dobutamine - Beta 1 agonist only 

Term

Which of the following bronchodilators is considered the safest for use in an animal with cardiac disease?

A) Isoproterenol

B) Terbutaline 

C) Ephedrine

D) Epinephrine 

Definition

Answer: B) Terbutaline 

This is because terbutaline is selective agonist for Beta 2 receptors to cause bronchodilation only. 

A) Isoproterenol & D) Epinephrine stimulate Beta 2 but also have strong effect on Beta1s which would put more stress on the heart. 

C) Ephedrine - works primarily on beta 2 receptors that stimulate release of NE so this would activate all adrenergic receptors (alpha1,2, beta1,2)

Term

Nicotinic receptors are found in all of the following locations, except:

A) Parasympathetic ganglia 

B) Sympathetic ganglia 

C) Skeletal muscle

D) Bronchial smooth muscle 

E) Adrenal medulla

 

 

Definition

Answer: D) Bronchial smooth muscle

The bronchial smooth muscle has muscarinic or adrenergic receptors as effector cells.  

 

All other have ACh released onto their nicotinic receptors

Term

Which of the following autonomic drugs would be most likely to increase myometrial contractility?

 

A) Atropine

B) Dobutamine

C) Ractopamine 

D) Xylazine 

Definition

Answer D) Xylazine which is an alpha agonist and alpha 1 receptors evoke smooth muscle contractions of the uterus

(add this to the list of abortion methods...)

 

A) atropine - is a muscarinic receptor antagonist

B) Dobutamine - beta 1 agonist

C) Ractopamine - Beta 2 agonist

 

 

Term

Which of the following is the sign of bethanechol stimulation of muscarinic receptors?

A) Skeletal muscle twitching 

B) Urination 

C) Constipation 

D) Dry Mucous mumebranes 

Definition

Answer: B) Urination - muscarinic receptors increase the contractions of the bladder and relax urinary sphincter - (more secretion!!)

A) skeletal muscle twitching (fasiculations) would be seen with a cholinesterase inhibitor (ACh not broken down and continuously stimulating)

C) Constipation - muscarinic receptors increase GI motility

D) Dry mucous membwanes - muscarinic receptors increase secretions

Term

Which of the following muscarinic receptors subtypes mediates the bethanechol-induced decrease in heart rate and contractility?

A) M1

B) M2

C) M3 

Definition

Answer: B) M2

M2 receptors are found on the heart 

 

M1 - is found mostly in the GI tract 

M3 - is everywhere else (but mostly smooth muscle) 

Term

Which of the following adrenergic receptors sutypes mediates the phenylpropanolamine-induced contraction of the trigone and sphincter muscle of the urinary bladder, a treatment for urinary incontenance?

A) Alpha 1 

B) Alpha 2 

C) Beta 1 

D) Beta 2 

Definition

Answer: A) Alpha 1 

Alpha 1 receptors are present on the urinary sphincter and bladder and respond by contracting the sphincters. 

Term

Which of the following would be most likely to increase airway resistance in a dog with pulmonary obstruction?

A) Albuterol 

B) Atenolol

C) Isoproterenol

D) Phenoxybenzamine 

E) Propranolol

Definition

Answer: E) Propranolol - which is an ANTAGONIST to Beta receptors.  This would block the beta 2s responsible for creating bronchodilation. 

A) Albuterol is a a beta2 AGONIST and would evoke bronchodilation 

B) Atenolol is only a beta 1 antagonist - no effect

C) Isoproterenol is a beta agonist - would help 

D) Phenoxybenzamine is an alpha 1 antagonist - no effect

Term

Which of the following Beta2 adrenergic agonists can be used legally as a repartitioning agent in cattle and swine and doesnt require a preslaughter withdrawl? 

(repartioning - leaner muscles from glycolysis)

A) Albuterol 

B) Clenbuterol 

C) Ractopamine 

D) Terbutaline 

Definition

Answer: C) Ractopamine - causes increased glycolysis

A) Albuterol - used for bronchodilation, too short acting to cause muscle glycolysis 

B) Clenbuterol - DOES cause repartitioning but has a LONG withdrawl and is illegal 

D) Terbutaline - is used for its bronchodilation properties and is also too short to cause repartitioning 

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