Pharmacology of ANS Flashcards
parasympathetic receptors
- muscarinic
parasympathomimetic
- aka cholinergic - mimic acetylcholine
- drugs that act as agonists at muscarinic receptors
- mimic actions of the PNS
- 2 major classes: cholinergic agonists and anticholinesterases
parasympatholytic
- aka anticholinergic - block acetylcholine
- drugs that act as antagonists at muscarinic receptors
- interrupt parasympathetic nerve impulses in the CNS and ANS
- prevent acetylcholine from stimulating cholinergic receptors
M2 receptor locations
- heart
- PSNS effector cells
- cardiac muscles
M3 receptor locations
- smooth muscle and exocrine
- intestinal smooth muscle and glands
cholinergic agonists
- mimic the action of acetylcholine
anticholinesterases
- inhibit the destruction of acetylcholine by blocking acetylcholinesterase
action of cholinergic drugs
- stimulate muscle contraction in target organs: parotid gland, eye, bladder, GI tract
- SLUDD: salivation, lacrimation, urination, defecation, digestion
clinical use of cholinergic drugs
- stimulate GI motility and gastric emptying
- stimulate bladder emptying
- constrict pupil (some forms of glaucoma)
action of anticholinergic drugs
- relax muscles in target organs: parotid gland, eye, bladder, GI tract
- ADBUCT: anhidrosis (lack of sweeting), blurry vision (mydriasis/dry eye), dry mouth (decreased salivation), urine retention, constipation (ileus), tachycardia
clinical uses of anticholinergic drugs
- bronchodilation
- stop diarrhea
- antiemetics (stop vomiting)
- cause mydriasis (pupil dilation)
- treat bradycardia (low hr)
sympathetic receptors
- alpha adrenergic: a1 and a2
- beta adrenergic: B1 and B2
adrenergic agonist drugs
- aka sympathomimetics
- mimic action of the SNS
- 3 major classes
3 classes of sympathomimetic drugs
- direct-acting: directly stim adrenergic receptors
- indirect-acting: stimulate the release of NE from nerve endings in the synapse
- dual-acting: do both
specificity of adrenergic agonist drugs
- can work at one specific subtype of receptor, alpha or beta subtypes, or be a nonspecific agonist
- specificity determines clinical use
a1 adrenergic agonist receptor location
- blood vessels
- eye
a1 adrenergic agonist actions
- vasoconstriction
- pupil dilation
a1 adrenergic agonist drug clinical use
- hypotension
- anti-arrhythmic
- mydriasis aka pupil dilation(weak, species specific)
a1 adrenergic agonist drug adverse effects
- hypertension
- arrhythmias
- CNS stimulation
a2 adrenergic agonist drug receptor location
- CNS
- pancreas
a2 adrenergic agonist drug action
- decreased sympathetic outflow
- decreased NE release
- decreased insulin secretion
- stimulation of receptors causes sympathetic inhibition!!! (weird one)
a2 adrenergic agonist drugs clinical use
- sedative
- analgesic
- muscle relaxation
- anxiolysis
a2 adrenergic agonist drugs adverse effects
- initial hypertension (high bp) which results in a baroreceptor-mediated reflex bradycardia (slow hr)
- leads to dec bp and CO
- arrhythmias
- vomiting (can be used to make cats vomit)
- increase urine output
- transient hyperglycemia
- increased myometrial tone and intrauterine pressure
B1 adrenergic agonist drugs receptor locations
- heart
- kidney
B1 adrenergic agonist drug action
- increased heart rate
- increased heart contractility
- increased renin release
B1 adrenergic agonist drug clinical uses
- hypotension - when under anesthesia or shock
- bradycardia
B1 adrenergic agonist drugs adverse effects
- hypertension
- tachycardia/arrhythmias
B2 adrenergic agonist drugs location
- lungs
- uterus
- blood vessels (not brain or skin)
B2 adrenergic agonist drug actions
- bronchodilation (main use)
- uterine relaxation
- vasodilation
b2 adrenergic agonist drug clinical uses
- respiratory disease/asthma
- delaying parturition (birth)
b2 adrenergic agonist drug adverse effects
- tachycardia/myocardial necrosis
- CNS excitement
- muscle tremors
trick for beta adrenergic agonist drugs
- we have 1 heart but 2 lungs
sympathetic receptors hint
alpha 1 - time to run
alpha 2s - time to snooze
beta 1 - hearts are achieving
beta 2 - means better breathing
adrenergic antagonist drugs
- aka sympatholytic drugs
- block actions of SNS
- most drugs in this class will be specific for either alpha or beta receptors
alpha adrenergic antagonists
- “alpha blockers”
- alpha 1 antagonists
- alpha 2 antagonists
alpha 1 antagonists
- treat congestive heart failure/hypertension; treat urine retention
alpha 2 antagonists
- reverse the sedation and bradycardic effects of alpha-2 agonists
beta adrenergic antagonists
- “beta blockers”
- beta 1 antagonists
- beta 2 antagonists
beta 1 antagonists
- treat congestive heart failure/ arrhythmias
beta 2 antagonists
- no specific uses
- most beta1 have beta 2 antagonist ability
- use with caution in asthmatic patients
epinephrine
- nonspecific adrenergic agonist
- increases hr and bp
- causes bronchodilation
- decreases GI motility
- dilates pupil
- used in ER
atropine
- nonspecific cholinergic antagonist
- increases hr and bp
- causes bronchodilation
- decreases GI motility
- dilates pupil
- used in ER
