"A naturally occurring xanthine derivative with central nervous system (CNS) stimulating activity. Due to the structural similarity to adenosine, caffeine binds to and blocks adenosine receptors, thereby preventing the inhibitory effects of adenosine on nerve cells. This leads to stimulation of medullary, vagal, vasomotor, and respiratory centers in the brain; and the release of epinephrine. Physiologic responses can include bradycardia, tachycardia, vasoconstriction, CNS excitablility, increased respiratory rate, increased blood pressure, increased blood flow to muscles, decreased blood flow to skin and inner organs, and release of glucose by the liver. Due to the interaction between adenosine A2A and dopamine D2 receptors, caffeine can also indirectly increase the levels of dopamine in the brain.NCI" . _:b656321 . "3G6A5W338E"^^ . . _:b656324 . . "Pharmacologic Substance"^^ . "CaffeinePTCRCH" . . "3,7-Dihydro-1,3,7-trimethyl-1H-purine-2,6-dioneSNNCI" . "CAFFN"^^ . "C8H10N4O2"^^ . "CaffeinePTNCI" . . "C328"^^ . "Caffeine"^^ . "C0006644"^^ . "262"^^ . "FDA"^^ . "40817"^^ . _:b656321 . "CHEBI:27732"^^ . "caffeinePTNCI-GLOSSCDR0000454809" . "TheineSYCRCH" . _:b656321 . _:b656322 . "Caffeine"^^ . _:b656323 . "A naturally occurring xanthine derivative with central nervous system (CNS) stimulating activity. Due to the structural similarity to adenosine, caffeine binds to and blocks adenosine receptors, thereby preventing the inhibitory effects of adenosine on nerve cells. This leads to stimulation of medullary, vagal, vasomotor, and respiratory centers in the brain; and the release of epinephrine. Physiologic responses can include bradycardia, tachycardia, vasoconstriction, CNS excitability, increased respiratory rate, increased blood pressure, increased blood flow to muscles, decreased blood flow to skin and inner organs, and release of glucose by the liver. Due to the interaction between adenosine A2A and dopamine D2 receptors, caffeine can also indirectly increase the levels of dopamine in the brain.MSH2002_06_01" . _:b656324 . _:b656323 . . _:b656322 . "A substance found in the leaves and beans of the coffee tree, in tea, yerba mate, guarana berries, and in small amounts in cocoa. It can also be made in the laboratory, and is added to some soft drinks, foods, and medicines. Caffeine increases brain activity, alertness, attention, and energy. It may also increase blood pressure, heart rate, breathing rate, and the loss of water from the body in urine.NCI-GLOSS" . "40817"^^ . "mg"^^ . _:b656322 . _:b656323 . "CAFABNCI" . "Organic Chemical"^^ . _:b656323 . "TrimethylxanthineSYCRCH" . "1,3,7-trimethylxanthineSNNCI" . _:b656321 . "5036"^^ . . "CAFFEINESYDTPNSC0005036" . "CaffeinePTDCP00344" . "CRCH"^^ . _:b656324 . . "An alkaloid stimulant having a purine double-ring structure composed of eight carbons and four nitrogen atoms with methyl groups attached to the nitrogen atoms at the 1, 3, and 7 positions and having double bonds at the carbons in positions 2 and 6.CRCH" . _:b656324 . "Caffeine"^^ . "CAFFEINEPTFDA3G6A5W338E" . _:b656322 . "MethyltheobromineSYCRCH" . . "58-08-2"^^ .