Caffeine.

 

Caffeine, 1,3,7-trimethylxanthine, is widely distributed in natural products, i.e, tea, coffee, cocoa and as an additive in many soft drinks. During preparation of coffee and tea, the strength of brew influences the caffeine content of the beverage. Standard average caffeine contents per cup of these beverages are listed right. As normally ingested from food sources, caffeine shows a variety of biological effects those have attracted the interest of pharmacologist and clinicians. 

Caffeine is regard as follows; ･ Diuretic ･ Cardiac muscle stimulant ･ Central nervous system stimulant

■Effect on Sleep: Much interest also has been concerned in the possible role of caffeine intake to central nervous system. In adults, the most sensitive function modified by caffeine is going to sleep. In one experiment, caffeine or placebo was taken blindly 0.5 hr before retiring, and the time of going to sleep was assessed by questionnaires next morning. Sleep postponement in adults has been detected following ingestion of about 100 mg caffeine 0.5 hr before retiring, but not at lower intakes. 

■Effect on Spontaneous Motor Activity: Using mice as an animal model, Sagesaka et al. showed that a single oral administration of caffeine at the dose of 4 mg/kg increased the number of revolutions of the tread wheel at 30 min intervals, suggesting that caffeine induced the spontaneous motor activity in mice.