Effects of barbiturates, phencyclidine, ketamine and analogs on cerebral circulation and cerebrovascular muscle.Altura BT, Altura BM. Although barbiturates are often effective as therapeutic agents in several types of brain ischemia, there is no consensus as to their mechanisms of action.he latter may be important in the salutory actions of barbiturates in brain ischemia, head trauma and cerebrovasospasm. Unlike barbiturates, ketamine was found to exert spasmogenic actions on cerebral arteries, which may aid in explaining the inability of this anesthetic to be of therapeutic value in brain ischemia.
Understory (or understorey, underbrush) in forestry and ecology comprises plant life growing beneath the forest canopy without penetrating it to any extent.Plants in the understory comprise an assortment of seedlings and saplings of canopy trees together with specialist understory shrubs and herbs.Young canopy trees often persist in the understory for decades as suppressed juveniles until an opening in the forest overstory permits their growth into the canopy.lants in the understory comprise an assortment of seedlings and saplings of canopy trees together with specialist understory shrubs and herbs. Young canopy trees often persist in the understory for decades as suppressed juveniles until an opening in the forest overstory permits their growth into the canopy.
Aboveground â Carbon is stored in the leaves, stems, and other parts of plants when they absorb CO 2 from the atmosphere and use it to grow. Trees are very important for carbon sequestration because they live a long time and can store their carbon for many years.Long-lived products â Wood and other products made from trees still contain the carbon absorbed by the plants that they came from.When a tree is utilized for wood, its ability to sequester carbon is extended, and the carbon is not released until the product burns or decomposes.ong-lived products â Wood and other products made from trees still contain the carbon absorbed by the plants that they came from. When a tree is utilized for wood, its ability to sequester carbon is extended, and the carbon is not released until the product burns or decomposes.