Membrane Potential: The charge difference the cytoplasm and extracellular fluid in all cells, due to the differential distribution of ions. Membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substance.
Messenger RNA (mRNA): A type of RNA synthesized from DNA in the genetic material that attaches to ribosomes in the cytoplasm and specifies the primary structure.
Molarity: A common measure of solute concentration, referring to the number of moles of solute in 1litre of solution.
Mutagen/Mutagenic: A substance/property of a substance that causes some type of mutation in the genetic material of an organism exposed to it.
Mutation: A change of one of the "letters" in the DNA "recipe" caused by chemicals, ultraviolet light, x-rays or natural processes.
Myocardium: The middle and thickest layer of cardiac muscle in the heart wall.
Neuron: A nerve cell; the fundamental unit of the nervous system, having structure and properties that allow it to conduct signals by taking advantage of the electrical charge across its cell membrane.
Neurotransmitter: A chemical messenger released from the synaptic terminal of a neuron at a chemical synapse that diffuses across the synaptic cleft and binds to and stimulates the post-synaptic membrane.
Occlusion: Constriction or blockage as can occur in a blood vessel.
Orphan Drug: A drug for which the target population is limited or for which the disease it treats occurs only rarely.