Drug Terminology, Receptors And Autonomic Nervous System Flashcards
What is Pharmacodynamics?
- Study of biochemical, cellular and physiological effects of drugs and their mechanisms of action
*what a drug does to the human body (how the drug interacts with the patients)
What is the definition of a drug?
A synthetic or natural substance that has a physiologic affect when administered to the human body
What is a receptor?
A cellular macromolecule or macromolecule complex with which a drug interacts to elicit a cellular or system response
*The site of action of a drug
*lock
What is a ligand
A substance (usually endogenous) that activates a receptor producing a physiologic response
*key
What does drug therapy do to the “lock and key”
Drug therapy will attempt to mimic the effects of the ligands or interfere with the effects of the ligand
*drugs are used to help us unlock the door or we use drugs to prevent the door from being unlocked
What is an agonist?
- A drug that binds to physiologic receptors and mimics the regulatory effects of the endogenous ligand
*there will be a biological response
What will happen if there is an increasing concentration of agonists?
It will increase the biological response until
*there are no more receptors for the agonist to bind OR
*maximal response has been reached
What is a partial agonist?
- Drug that binds to the receptors and mimics the effects of the ligand to a LESSER DEGREE than a true agonist
*will NOT produce 100% of the biologic response even at high doses
What is an antagonist?
A drug that blocks or reduces the action of an agonist or ligand
*there will be NO biological effect
*antagonist block the effect from happening
What are the different types of antagonist?
- Reversible
*competitive
*Non-competitive - Irreversible
What is the def of efficacy and potency
E: the maximum response a drug can produce
P: measure of the dose required to produce a response
EX: Drug A produces complete eradication of PVC at dose of 10mg
Drug B produces complete eradication of PCS at dose 20mg
*Both drugs have the same efficacy
*Drug A is more potent than drug B
What is Affinity?
The strength with which the drug binds to the receptor
*If a drug has a low dissociation constant it will have a high affinity
What is the drugs affinity determined by
The drugs chemical structure
What type of specificity will a drug have if it has a high affinity for a specific receptor only found in a limited number of cells?
high specificity
What type of specificity will a drug have if it has a high affinity for a specific receptor only found in numerous cells?
Low specificity
*drug will have widespread effects, SE
What can drug responsiveness change due to?
- Disease
- Age
- Pervious drug adminsitration
- Genetics
What are pharmacokinetic interactions?
Delivery of a drug to its site of action is altered by a second drug
*EX: metformin interferes with the absorption of B12
What are pharmacodynamic interactions?
Response of the drug target is modified by a second drug
EX: Nitroglycerin and sildenafil together will drastically decrease BP due to a lot of vasodilation
What are pharmacogenomic interactions
A persons genome alters their ability to absorb, distribute, metabolize and/or eliminate a drug
What are neurotransmitters?
- Chemicals synthesized and stored in neurons
- They are released from axon terminus into the synaptic cleft in response to action potential
- They interact with receptors
- The produce physiologic responses in innervated tissue
What is the systemic for maintaining homeostasis?
ANS
*ANS innervates all organs in the body (except skeletal)
*Movement for things that occur without conscious control
What is the autonomic (visceral) reflex?
Functional unit of the ANS
1. Afferent fibers from periphery to CNS (sensory)
2. CNS integration
3. Efferent fibers from CNS to periphery
What is the Efferent Nerve arrangement?
- Preganglionic neuron
- Ganglion
- Postganglionic neuron
- Effector organ
*For smooth muscle, cardiac muscle, vascular endothelium and glands
Where do preganglionic axons originate from the PNS
In the brain and sacral spinal cord
*Ganglion is often within the effector organ
*fewer postganglionic neurons resulting in discrete responses
Where do preganglionic axons originate from the SNS?
In the thoracic and lumbar cord
*Ganglion are distant from effector organ
*larger number of postganglionic neurons resulting in widely distributed responses
What is does the somatic nervous system innervated?
Skeletal muscle
*no peripheral ganglia
*rapid transmission allows for rapid control of motor units
*voluntary movements
What is the neurotransmitter of the PNS? (Cholinergic)
Cholinergic nerves
*Acetylchoine
What are the location of acetylcholine (ach)
- Preganglionic neurons to all ganglia
- Postganglionic parasympathic neurons
- Preganglionic fibers to adrenal medulla
- Postganglionic sympathetic neurons to sweat glands
- Somatic motor neurons
What is the neurotransmitter of the PNS? (Adrenerigc)
- Norepinephrine
What are the locations of NE
- Postganglionic sympathetic neurons
- Also released from adrenal medulla
What cells are released from the adrenal medulla?
- Medullary cells synthesize and release two catecholamines into circulation
*Epinephrine (80%)
*Norepinephrine (20%)
What are medullary/chromaffin cells also called?
Neuroendocrine cells
Where are neuroendocrine cells found?
Found in the medulla of the adrenal gland
What will not be made if there is not enough choline?
ACH
*choline is made in the diet
What will happen if there is a drug that blocks the affects of ACH?
There will be an increase in the amount of ACH and increase the message rate of ACH
What will happen if there is a drug that increases the effects of ACHase?
There will be a decrease in the amount of ACH and decrease the message of ACH
What is alpha 1 receptor function?
- Vasoconstriction
What is alpha 2 functions ?
- Decreased release of NE from sympathetic neurons
What is Beta 1 function?
- Increased heart rate
- Increased heart contractility
What is beta 2 function?
- Bronchodilation
What is Muscarinic 2 function?
- Decreased heart relate
- Decreased atrial contraction
What is muscarinic 3 receptor function?
- Activates sweat gland
- Increases GI motility
- Increases bladder contraction
- Bronchoconstriction
Where are nicotinic n receptors found ?
- In al autonomic ganglia
Where are nictoctinic M receptors found?
- At neuromuscular junction
