Small doses raise blood pressure.
Large doses lower it. Area, Bighorn Canyon National Recreation Area, Black Canyon Of The Gunnison, Canyonlands National Park, Cape Cod National Seashore, Capital Reef National Park, Carlsbad Caverns National Park, Casa Grande National Monument, Channel Island National Park, Chiricahua National Monument, Colorado National Monument, Coulee Dam Nat. Area, Death Valley National Monument, Ebey's Landing National Historic River, El Morro National Monument, Europe, Fire Island National Seashore, Fort Bowie National Historic Site, Fort Union National Monument, Gateway National Recreation Area, Gila Cliff Dwellings National Monument, Glacier National Park, Glen Canyon National Recreation Area, Golden Gate Natl. Point Reyes National Seashore, Rainbow Bridges National Monument, Redwood National Park, Richmond National Battlefield Park, Rock Creek Park, Rocky Mountain National Park, San Juan Island National Historic Park, Santa Monica Mounatins Nat.