Physiology of ethanol and nicotine Flashcards
What is nicotine
A naturally occuring plant alkaloid found in potato, tomato and tobacco
Describe nicotine metabolism
Mostly oxidated to cotinine, 50% of nicotine is excreted in urine.
How can nicotine affect the organism as a whole
Increased hart rate, cardiac contractility, BP, bobilisation of blood sugar, and decreased skin temp
Arousal or relaxation
What does the parasympathetic nervous system do generally?
What neurotransmitter does it use
Reduces/inhibits
Acetylcholine
What does the sympathetic nervous system do generally
What neruotransmitter does it use
activate
Noradrenaline/norepinephirine
What are the two types of choligernic receptors
Nicotinic (nAChR)
Muscarinic
What are the two types of nAChR
Nm receptors (neuromuscular junction)
Nn receptors (autonomic ganglia, adrenal gland, CNS)
How do peripheral effects arise
Stimulation of autonomic ganglia and peripheral sensory receptors mainly in heart and lungs
Name some of the pathophysiological conditions from smoking
Dependence,
CHD, Peripheral vascular disease, lung cancer, COPD (chronic bronchitis, emphysema)
Abnormal foetal development
What is the recommendations for alcohol intake
2-3 units/day
How much ethanol is metabolised
90%, ocurring in the liver.
How does alcohol affect the cardiovascular system
Cutaneous vasodilation, warm feeling which is really heat loss
How does alcohol affect the endocrine systems
Diuresis
How does alcohol affect the GI tract
Increases salivary and gastric sec
How does alcohol affect the liver
Increased fat accumulation, heppatitis, hepatic necrosis and fibrosis
How can alcohol affect foetal development
Foetal alcohol syndrome, alcohol-related neurodevelopmental disorder
What are the acute alcohol intoxication effects on CNS
Well known, when you get drunk
What are the chronic effects of alcohol on CNS
Irreversible neurological effects (demetia, peripheral neuropathy)
What is the mechanism of action of alcohol on the CNS?
Depressant effects, GABA-mediated inhibition similar to benzodiazepines
The benzodiazepine flumazenil is used to reverse the depressant effects
Alcohol works on CNS by inhibiting transmitter release in response to nerve terminal depolarisation by inhibiting opening of voltage dependent calcium channels in neurons
Describe the pathophysiology of alcohol
Dependence
\+++ risk of CNS atrophy, Peptic ulcers Cardiomyopathy Pancreatitis Liver damage Varices (enlarged/swollen veins) Testicular atrophy
What is tolerance
Decrease in pharmacological effect on repeated administration of drug, has to be increased in dose to get the same effect.
What is dependence
When drug-taking becomes compulsive, taking precedence over other needs
Withdrawal/abstinence syndrome
Adverse effects (physical or psychological after taking the drug)
What is craving
Intesne desire for a drug that outlasts the withdrawal syndrome
Which pathway do dependence producing drugs work upon
Mesolimbic/mesocortical dopaminagenic pathway
How is nicotine addictive
It enhances synthesis and release of dopamine, acting on dopamine cell bodies.
How can people become alcohol dependent
Alcohol decreases the activity of GABAergic interneurons
What are the three stages of alcohol withdrawal
1: Tremor, nausea, sweating, fever, maybe hallucinations
2: Epilepsy like seizures
3: Delerium tremens (confusion, agitation, aggression and more severe hallucinations
