NMDA reÂ·cepÂ·tor. a type of glutamate receptor that participates in excitatory neurotransmission and also binds N-methyl-d -aspartate; may be particularly involved in the cell damage observed in individuals with Huntington disease.
â Ultramafic magma is extremely low in silica, with less than 45 percent of the same, but rich in heavier elements like iron and magnesium. It can have a temperature of about 2732 Â°F. It has very low viscosity and thus, its eruptive behavior is gentle.
What are planets made of? A: Quick Answer. The inner planets, Mercury, Venus, Earth and Mars, are made up of silicate rock and heavy metals such as iron and nickel, whereas the outer planets, Jupiter, Saturn, Uranus and Neptune, are made up mostly of gases, according to Universe Today.