Exam 2 Flashcards
Define neuropharmacology
The study of drugs that alter processes controlled by the nervous system
Two categories neuropharmacology is divided into
PNS drugs
CNS drugs
Main divisions of the PNS
Somatic motor system
Autonomic motor system
Divisions of the autonomic nervous system
Parasympathetic
Sympathetic
3 basic functions of the autonomic nervous system
Regulate heart
Regulate secretory glands
Regulate smooth muscles
7 basic functions of the parasympathetic nervous system
(Slowing down, rest and digest)
- slowing heart rate
- increasing gastric secretions
- emptying the bladder
- emptying the bowel
- focusing the eye for near vision
- constricting the pupil
- contracting the bronchial smooth muscle
What do parasympathetic nervous system drugs help with?
Digestion of food
Excretion of waste
Control of vision
Conservation of energy
3 main functions of the sympathetic nervous system
Regulation of cardiovascular system
Regulation of body temperature
Implementation of fight or flight reaction
How does the sympathetic nervous system regulate the cardiovascular system?
Maintaining blood flow to the brain
Redistributing blood
Compensating for the loss of blood
How does the sympathetic nervous system regulate body temperature?
Regulates blood flow to skin
Promotes secretion of sweat
Induces piloerection (erection of hair)
How does the sympathetic nervous system implement the fight or flight reaction?
Increasing heart rate and blood pressure
Shunting blood away from skin and viscera
Dilating bronchi
Dilating pupils
Mobilizing stored energy
Example of dual innervation (where sympathetic and parasympathetic are opposed)
Heart rate
Example of dual innervation (where sympathetic and parasympathetic are complementary)
Erection/ejaculation
Example of innervation and regulation by only one division: sympathetic nervous system
Blood vessels
What is feedback regulation?
Allows system to adjust by responding to incoming information
Example of feedback regulation
Baroreceptor reflex - helps regulate blood pressure
(Baroreceptors are located in carotid sinus and aortic arch)
What is autonomic tone?
The steady, day to day influence exerted by the ANS on a particular organ or organ system
Function of autonomic tone
Provides a basal level of control over whichever branch of the ANS has the most influence
(aka predominant tone in organs that are controlled by both the SNS & PNS)
What is the predominant tone in most organs?
The parasympathetic nervous system
What is the predominant tone in the vascular system?
Sympathetic nervous system
Two categories of receptors in the Peripheral nervous system
Cholinergic receptors
Adrenergic receptors
What are cholinergic receptors mediated by?
Acetylcholine
What are adrenergic receptors mediated by?
Epinephrine
Norepinephrine
Dopamine
What are the neurotransmitters of the PNS?
Acetylcholine
Norepinephrine
Epinephrine
Where are acetylcholine neurotransmitters employed?
At most junctions of the PNS
Where are norepinephrine neurotransmitters released?
By most postganglionic neurons
Where are epinephrine neurotransmitters released?
By the adrenal medulla
Cholinergic receptor subtypes
Nicotinic(N)
Nicotinic(M)
Muscarinic
Function of nicotinic(N) receptors
Where are they located?
Activate neural activity
In ganglia of the ANS
Function of Nicotinic(M) receptors
Where are they located?
Activate muscular activity
At neuromuscular junctions
Function of muscarinic receptors
Where are they located?
Activate muscarinic receptors at organs
On organs regulated by PNS
Types of adrenergic receptors
Alpha1
Alpha2
Beta1
Beta2
What do alpha1 receptors control?
Vasoconstriction
Contraction of bladder neck and prostate
Where are alpha2 receptors located?
In presynaptic junction
Where are beta1 receptors located?
Heart
Kidneys
Function of beta1 receptors in the heart
Increase heart rate
Increase force of contraction
Increase velocity of conduction in AV node
Function of beta1 receptors in the kidney
Renin release
Function of beta2 receptors
Bronchial dilation
Relaxation of uterine muscle
Vasodilation
Glycogenolysis
Function of dopamine receptors
Dilate renal blood vessels
Which adrenergic neurotransmitters are activated by epinephrine?
All alpha and all beta receptors
Which adrenergic neurotransmitters are activated by norepinephrine?
Alpha1
Alpha2
Beta1
Which adrenergic neurotransmitters are activated by dopamine?
Alpha1
Beta1
Dopamine
What are cholinergic drugs?
Agents that influence the activity of cholinergic receptors
How to most cholinergic drugs work?
Most mimic or block the actions of acetylcholine
Function of cholinesterase inhibitors
Prevent the breakdown of acetylcholine
How do muscarinic agonists work?
By direct interaction with muscarinic receptors
What is another name for muscarinic agonists?
Parasympathomimetic agents (mimics something in the parasympathetic nervous system)
Prototype drug for muscarinic agents
Bethanechol (Urecholine)
Action of Bethanechol (Urecholine)
Selective agonist at muscarinic cholinergic receptors
Effects bethanechol has on the body
Heart - bradycardia
Lungs - constriction of bronchi
GI system - increased tone and motility
Bladder - contraction of detrusor muscle and relaxation of trigone and sphincter
Exocrine glands - increased secretions
Eye - miosis (pupillary constriction) & contraction of ciliary muscle (for near vision)
Therapeutic uses of bethanechol
Urinary retention
Investigational gastrointestinal uses
Adverse effects of bethanechol
Hypertension
Increased tone and motility of GI system (nausea, diarrhea)
Exacerbation of asthma
Dysrhythmias in patients with hyperthyroidism
Other names for drugs that are muscarinic antagonists
Anticholinergic drugs
Parasympatholytic drugs
Antimuscarinic drugs
Muscarinic blockers
Function of anticholinergic drugs
Competitively block the actions of acetylcholine at muscarinic receptors
Where are muscarinic antagonists located?
Most are on structures innervated by parasympathetic nerves
Prototype for muscarinic antagonists
Atropine
Action of atropine
Affects muscarinic receptor blockade
Effects of atropine on the body
Heart - increases heart rate
Lungs - relaxes bronchi
GI system - decreases tone and motility
Bladder - decreases tone of detrusor muscle
Exocrine glands - decreases secretions
Eye - Mydriasis and cycloplegia (paralysis of the ciliary muscle of the eye)
CNS - mild excitation to hallucinations and delirium
