Cholinergic Pharmacology 2&3 Flashcards
What are the characteristics of cholinergic receptors?
- Receptors that bind the ACh and mediate its actions
- consist of nicotinic and muscarinic receptors
What is the difference between mydriatics and miotics?
-
Mydriatics: Dilates the pupils (open pupils)
- contraction of dilator, relaxtion of sphincter
-
Miotics: Constricts pupils (closes pupils)
- contraction of sphincter, relaxation of dilator
How does the ANS regulate pupil function?
- Pupillary diameter is controlled by the spincter pupillae (PNS) and dilator pupillae (SNS)
What is the Division of Cholinergic Antagonist?
- Muscarinic Antagonists
- Nicotinic Antagonists
- Ganglionic blocking agents
- Neuromuscular blocking agents
What are the names of cholinergic blockers and what are their functions?
- Anticholinergics, parasympatholytics, antimuscarin
- Function: block the actions of ACh
What is myasthenia gravis?
- An autoimmune disease
- Body makes antibodies against nicotinic receptors blocking their action
- Proper contraction of eye lid muscles is prevented
What are the toxic effects of anti-muscarinic drugs?
- “dry as a bone”
- “red as a beet”
- “mad as a hatter”
- “dry as a bone”: result of decreased sweating, salivation and lacrimation
- “red as a beet”: result of dilation of cutaneous vessels of the arms, head, neck and trunk
- “mad as a hatter”: result of CNS effects such as sedation, amnesia, delirium, hallucination
What are three major muscle types and where are they located?
- Smooth muscle: muscarinic receptors
- surrounding organs, major muscle in GIT
- Cardiac muscle: nicotinic receptors
- occurs in walls of heart
- Skeletal muscle: nicotinic receptors
- attached to skeleton
What is the autonomic regulation of the three major muscle types?
- Smooth muscle: involuntary
- Cardiac muscle: involuntary
- Skeletal muscle: voluntary
How do nicotinic receptors increase calcium levels?
(cardiac and skeletal muscles)
- Membrane depolarisation that is brought about by Na+ entrance into muscle activating voltage gated Ca2+ channels that increases Ca2+ inside the muscle
How do muscarinic receptors increase calcium levels?
(smooth muscles)
- GPCR: through the signalling event they empty the intercellular Ca2+ stores causing membrane depolarisation that is brought about by Na+ entrance into muscle activating voltage gated Ca2+ channels that increases Ca2+ inside the muscle
What is dystonia?
- Neurological movement disorder, where sustained muscle contractions cause twisting and repetitive movements or abnormal postures
What are the causes of dystonia?
- Hereditary
- Physical trauma
- Infection
- Poisoning
- Reaction to pharmaceutical drugs (particularly antipsychotics)
What are the basic features of Parkinson’s Disease?
Low level of neurotransmitter dopamine
What are the symptoms of parkinson’s disease?
- Bradykinesia: slowness in intiation and execution of voluntary movements
- Rigidity: increase muscle tone and increase resistance to movement
- Tremor
- Postural instability
- Gait Disturbance: shuffling feet
TRAP
tremor, rigidity, akinesia and bradykinesia, postural instability
What are extrapyramidal symptoms?
- Can be caused by low levels of dopamine as well as drugs that are antagonists of dopamine receptors e.g. antipsychotics
- Parkinsonism (TRAP)
What is the ANS regulation of smooth muscle?
- Sympathetic stimulation relaxes bronchial smooth muscle through the ‘increase’ in cAMP which blocks calcium-mediated constriction
What is the pathology of urinary incontinence?
What is it?
What can cause it?
- Involuntary urinary leakage
- When you hold urine, brain overrides reflex where the spinal cord sends signal for bladder to contract and therefore can cause bladder dysfunction
- Dementia, drugs, functional abnormalities of lower urinary tract
Describe the function of the bladder?
- When bladder is full, sphincter muscles stop urine from leaking by closing tightly around the neck of the bladder that opens to the urethra
What causes urination?
Stimultaneous constriction of bladder wall muscles and relaxation of urethral sphincter muscles
Describe urine filling/storage regulation by ANS
- Blocking of parasympathetic nerve (relaxation of detrusor bladder muscles)
- Activation of Sympathetic nerve (internal sphincter muscle constriction)
- Activation of somatic nerve (external sphincter muscle constriction)
Describe urination regulation by ANS
- Activation of parasympathetic nerve (constriction of detrusor bladder muscles)
- Blocking of Sympathetic nerve (internal sphincter muscle relaxation)
- Blocking of somatic nerve (external sphincter muscle relaxation)
What is the position of CRTZ in regard to blood-brain barrier?
Outside BBB
What are anti-cholinergic ADRs?
- Dry mouth
- Blurred vision
- Constipation
- Drowsiness
- Poor memory
- Anisocoria
