Účinky kofeinu
Kofein structurally similar to adenosine
- Can block the adenosine receptor
- Adenosine antagonism [1,2]
- Phosphodiesterases inhibition [2]
- It increases the intracellular calcium concentration
- Causes noradrenaline release
- Sensitizes dopamine receptors
- Positive inotropic and chronotropic effects na srdce [2]
- Can trigger arrhythmia [2]
- Antagonism of the A1 and A2A subtypes of the adenosine receptor
- Adenosine is an endogenous neuromodulator with mostly inhibitory effects
- Adenosine antagonism by caffeine results in effects that are generally stimulatory.
Povzbuzení - stimulans
- Srdecní slabosti
- Kolapsových stavech
- Bolestech hlavy
- Neuralgiích,
- Migrene
- Astmatických záchvatech
Snižuje adenosinovou transmisi v mozku
- Budivý úcinek
- Povzbuzující úcinek na CNS
- Vyvolávající pocit vitality a lepšího zvládnuti duševních i fyzických úkonu
- Zahání únavu nebo ji napomáhá lépe prekonávat,
- Potlacuje spánek
- Ciní jej povrchním a prerývaným [1]
Spalování energie
- Konzumace kávy zvyšuje základní látkovou premenu o nekolik %
- Tím i energetickou spotrebu o 80–150 kalorií [1]
- Na telesnou hmotnost má tento zvýšený energetický výdej jen minimální vliv [1]
Toxicity of oral caffeine in animals
- LD50
- 200–400 mg/kg in rats
- 185 mg/kg in mice [1]
- no observed adverse effect
- 150–174 mg/kg body weight/day in rats
- 167–179 mg/kg body weight/day in mice [1]
- Caffeine toxicity
- In rats - nad 100 days 110 mg/kg caffeine/d via intragastric cannulas
- Stressor reactions
- Adrenal cortex hypertrophy
- Thymic atrophy
- Gastric ulcer
- Hypertrophy of the salivary glands
- Hypertrophy liver
- Hypertrophy heart
- Hypertrophy kidney
- Hypertrophy lung [1]
Toxcita kofeinu u lidí
- Fatal blood concentrations of 80–100 mg/L in humans
- Person would need to ingest 50–100 tablets of 100 mg pure caffeine [1]
-Nálezy při fátální intoxikaci kofeinem:
- Only a few fatal caffeine intoxication cases have been reported in the literature
- Headache
- Nausea, vomiting
- Fever
- Hyperventilation, dizziness, anxiety, tinnitus, tremor
- Agitation
- Hypertension, hypotension, arrhythmia
- Seizures [1]
- Acute level of caffeine consumption is thought to be
- Approximately 10 g per day in adults
- Cca 100 cups of coffee [1]
- Difficult to determine the cause of death in patients who do overdose
- Blood caffeine concentrations can be used to help make a definitive diagnosis in such patients
- 15 case reports on attempted suicides that used caffeine
- Only 7 fatalities occurred [1]
- Pitva 18-year-old woman was found dead in her bed at home
- Známky zvracení, eroze a krvácení žaludku, edem mozku
- Nonspecific changes in many of the organs [1]
- Possible caffeine’s mechanism of death:
- Usually associated with ventricular arrhythmia
- Seizures may be another possible mechanism [1]
- Severe rhabdomyolysis
- Acute renal failure
- Brain showed edematous changes
- Respiratory arrest caused by caffeine-induced brain functional damage [1]