What are some of the most common chemical convulsants?
What is the mechanism of action for picrotoxin and pentylenetetrazol?
- Both picrotoxin and pentylenetetrazol are non-competitive inhibitors (may bind to target with or without ligand present) of Cl- channels associated with GABAa receptors.
- This causes disinhibition.
Both ____________ and ____________ are common ingredients found in rat poisons.
Strychnine and picrotoxin
Strychnine poisoning may result in _______________ and/or _______________.
- Risus sardonicus
_____________ is the severe hyperextension and spasticity in which an individual's head, neck, and spinal column enter into a complete "arching" or "bridging" position.
_________________ is the abnormal, sustained spasm of the facial muscles that appears to produce grinning.
What is the usual treatment for strychnine poisoning?
- Treat with diazepam (benzodiazepine)
- Reduce environmental stress
- Administer activated charcoal to deactivate chemical in digestive tract
What are the three common methylxanthines?
Methylxanthines are (man-made/plant products).
On average, there is approximately ___ mg of caffeine in a can of Coca Cola.
What are some of the cognitive effects seen in methylxanthine use?
- Increased capacity for intellectual effort
- Decreased reaction time
- Decreased fine motor coordination
- Decreased timing skills
- Decreased arithmetic skills
Methylxanthines (increase/decrease) the sensitivity of the body's medullary receptors to CO2.
- Increased sensitivity to CO2 causes increased stimulatory inputs to the respiratory center of the brain and increased respiration.
Methylxanthines cause a slight (increase/decrease) in heart rate.
Decrease, though this seems counterintuitive
Methylxanthines (dilate/constrict) peripheral vasculature to muscles, while they (dilate/constrict) cerebral vasculature.
Dilate peripheral vasculature
Constrict cerebral vasculature
Theophylline, a methylxanthine, (dilates/constricts) the bronchioles.
Methylxanthines (increase/decrease) the capacity for work in skeletal muscle.
Coffee, which contains caffeine, (inhibits/stimulates) peristalsis in the GI system.
What is the mechanism of action for methylxanthines?
Methylxanthines primarily function by acting as adenosine receptor antagonists. They also inhibit phosphodiesterases, increasing cyclic AMP and GMP. Lastly, at high concentrations they may cause release of intracellular Ca2+.
(T/F) Most effects of adenosine are the opposite of methylxanthines.
Adenosine (dilates/constricts) peripheral vasculature to muscles, while it (dilates/constricts) cerebral vasculature.
Constricts peripheral vasculature
Dilates cerebral vasculature
Methylxanthines usually experience a peak plasma concentration within ___-___ hours after ingestion.
(T/F) Genetic variability in the enzyme N-acetyltransferase may cause changes in methylxanthine half life.
Half life of methylxanthines may be increased by:
- Liver disease
- Oral contraceptives
Half life of methylxanthines may be decreased by:
- Combination with phenytoin or barbiturates
Caffeine half life in adults is typically ___-___ hours
Caffeine half life in pre-term infants is around ___ hours.
Toxic amounts of caffeine may cause (olfactory/gustatory/both) hallucinations.
Both olfactory and gustatory hallucinations
(Consumption of/Failure to consume) caffeine in non-tolerant individuals may cause headaches.
(Consumption of/Failure to consume) caffeine in tolerant individuals may cause headaches.
Failure to consume
What is the mechanism of action for nicotine?
Nicotine acts as an acetylcholine receptor agonist at Nicotinic Acetylcholine receptors.