Caffeine and Methylxanthines Notes PDF

CAFFEINE AND THE METHYLXANTHINES PSY3142 QUICK HISTORY • Coffee • Ethiopia (12th and 15th centuries) • Tea • China (780 A.D.) • Cocoa • Mayas, Aztecs, Incas (Pre-Columbian) • chocolate drink introduced to Spain in 1520 • S.J. Fry (1728): 1st Chocolate Factory in England AGENDA • Basics • Neuro...

CAFFEINE AND THE METHYLXANTHINES PSY3142 QUICK HISTORY • Coffee • Ethiopia (12th and 15th centuries) • Tea • China (780 A.D.) • Cocoa • Mayas, Aztecs, Incas (Pre-Columbian) • chocolate drink introduced to Spain in 1520 • S.J. Fry (1728): 1st Chocolate Factory in England AGENDA • Basics • Neuropharmacology • Effects • use 3 SOME BASICS 4 CAFFEINE Xanthine stimulant or methylxanthine Occurs naturally 1st isolated from coffee in 1820 Found in coffee, tea, and cocoa 5 SOURCES OF METHYLXANTHINES: COFFEE ARABICA AND CANEPHORA (ALSO CALLED ROBUSTA) • 2 types account for 90% of world’s coffee • Native to Ethiopia 6 SOURCES OF METHYLXANTHINES: TEA • Made from leaves of Camellia sinensis • Black (fermented) • Oolong (semifermented) • Green Chinese (unfermented) • Scented with flower petals • Jasmine • Also contains therophylline and theobromine in addition to caffeine 7 SOURCES OF METHYLXANTHINES: COCOA • Cocoa tree (seeds) • Native to tropical Amazon rain forest • Alkalize • contains theobromine and caffeine 8 OTHER NATURAL SOURCES OF METHYLXANTHINES • Ilex plant • Amazon region • Mate • Cassina • South America • Youpon or black tea • Guarana • Amazon, Orinoco, and Negro rivers in South America • Cola • Southern Nigeria WHERE ELSE CAN WE FIND IT? • Soft Drinks and Energy Drinks • Food Additives • Pudding mixes • Baked goods • Dairy desserts and candy • Medicines • • • • • • • Headache medicine Cold and flu Over the counter medicines (Anacin) Weight control aids Allergy relief compounds Stimulants Asthma medications NEUROPHARMACOLOGY ROUTES OF ADMINISTRATION • Oral* • Rectal suppository • Intramuscular or intravenous routes ABSORPTION • Lipid Soluble • Digestive System • Most from Intestines • Peak concentration blood levels about 30 mins DISTRIBUTION Caffeine crosses the blood-brain and placental barriers without difficulty and reaches all body organs • Present in all body fluids, including breast milk EXCRETION • Less than 2% of caffeine is excreted unchanged in the urine • Half life (2 ½ to 4 ½ hours) • Caffeine metabolism Slowed by alcohol Speeded by broccoli Smokers eliminate caffeine twice as fast as nonsmokers Elimination slowed during pregnancy Babies cannot metabolize caffeine well (85% excreted unchanged in urine, ½ life 4 days) • Adult metabolism develops 9 months • • • • • NEUROPHYSIOLOGY • Adenosine receptor blockers • Adenosine is used in many systems in the body commonly as a neuromodulator • Increases dopamine • Block benzodiazepine receptors in high dose • Effects on anandamide EFFECTS 17 EFFECTS OF CAFFEINE AND THE METHYLXANTHINES • Stimulating effect in the peripheral nervous system • E.g. increased heart rate, vascular system, dilates blood vesicles in body, constricts in brain • Mild stimulating effects in CNS • Via effects on adenosine and GABA modulatory systems • E.g. frontal lobe, motor areas, reward pathway • Effects on Human Performance and Behavior • Depend on factors including individual susceptibility, dose, time of consumption, and the nature of the task • Effects on Sleep • Insomnia • Wake up more easily CHRONIC USE • Not typically problematic for most people • Counter indicated for those with high blood pressure, pregnant, stomach ulcers, or certain drugs • Strong negative reinforcement to avoid withdrawal symptoms • These are short lived 19 TOLERANCE • Not pronounced for PNS effects • CNS effects develop tolerance quickly • Explains why people may tend to increase intake over time • Body requires more to generate the CNS stimulant effects from initial use 20 WITHDRAWAL DECREASE IN LOCOMOTOR ACTIVITY DISRUPTION OF ONGOING OPERANT RESPONDING HEADACHE (MOST COMMON SYMPTOM) DROWSINESS, DECREASED ENERGY, AND FATIGUE SYMPTOM SEVERITY IS DIRECTLY RELATED TO DOSE 22 WITHDRAWAL 23 • Changes in frequency of reported head-aches and scores on an “energy/active” scale of subjects for 24 days while they consumed 100-mg caffeine capsules, then a placebo, and then switched back to caffeine HARMFUL EFFECTS • Reproduction • Lowers birth rate • Breast milk • Cardiac disease • Debatable whether it causes heart disease HARMFUL EFFECTS • Bone Density • Bone loss and postmenopausal women • Caffeinism and Anxiety • Sensory disturbances • Caffeinism • Anxiety-related symptoms • Lethal • Lethal dose is between 3 and 8 grams (30 to 80 cups of coffee--6 deaths attributable to caffeine overdose • Convulsions and respiratory collapse CAFFEINE IN YOUNG PEOPLE A SPECIAL CONCERN • WHAT ARE THEY NOT GETTING IF THEY ARE DRINKING POP, COFFEE, ETC. • ENHANCED BEHAVIOURAL EFFECTS DUE TO LOWER BODY WEIGHT • INCREASED INCIDENCE OF OBESITY, DIABETES, MAYBE OSTEOPOROSIS IN LATER LIFE BENEFICIAL EFFECTS • Protective effects against Parkinson’s disease • Weight Loss 28 USE 29 USE • • • • • 80% of global population; 90% in North America consume caffeine regularly Average caffeine consumption is around 70-76mg/person/day * varies widely Most of this is coffee or tea Coffee is the second most common beverage after water! Kids do consume caffeine; typically, in the form of soft drinks but energy drinks are increasingly popular… TABLE 9.1 – FROM TEXT SOURCES OF METHYLXANTHINES AND THEIR CAFFEINE CONTENT 31 Source/Coffee Serving Size Caffeine Content Starbucks brewed coffee 16 fl. oz. (grande) 330 mg Dunkin’ Donuts brewed coffee 16 fl. oz. (medium) 178 mg McDonald’s brewed coffee 16 fl. oz. (medium) 145 mg Tim Hortons brewed coffee 14 fl. oz. (medium) 196 mg Folgers brewed coffee 8 fl. oz. 95 mg Folgers instant coffee 1.8 g (1 rounded tsp.) 57 mg BIG BUSINESS Product or Commodity Value of World Exports in United States Dollars Crude oil from various sources 1.4 trillion Medicines and pharmaceuticals 1.2 trillion Automobiles 434.4 billion Paper products 98.2 billion Pearls and precious stones 89.5 billion Textiles 38.0 billion Food and Agricultural Products Meat 101.4 billion Dairy products (milk and cheese) 54.5 billion Vegetables (Fresh, frozen and tubers) 86.4 billion Fish 68.4 billion Coffee and products containing methylxanthines 65.2 billion Alcoholic beverages 57.2 billion Wheat products 36.1 billion Tobacco 34.2 billion ____________________________________________________________________________ ETHICALLY SOURCED PRODUCTS 33 Understanding Fair Trade Logos - YouTube USE DISORDER? • Caffeine is the only drug that APA excludes from use disorder • Continues to be discussed/monitored • Other organizations do recognize caffeine dependency, e.g. WHO 34 SUMMARY • Basics • Neuropharmacology • Effects • Use 35