A three-nucleotide sequence in mRNA that specifies a particular amino acid or polypeptide termination signal; basic unit of the genetic code. In translation, an mRNA codon is â¦ recognized by its complementary tRNA anti-codon.
Epinephrine is an important cell signaling molecule in the fight or flight response. Also known as adrenaline, epinephrine is an efficient messenger that signals many cell types throughout the body with many effects. In the lungs, epinephrine binds to receptors on smooth muscle cells wrapped around the bronchioles.his increases the rate at which other chemical signals, glucose and oxygen are circulated to the cells that need them. Epinephrine also contracts specific types of muscle cells below the surface of the skin, causing beads of perspiration and raised hairs at the surface.
epinephrine. a hormone produced by the adrenal medulla; called also adrenaline (British). Its function is to aid in the regulation of the sympathetic branch of the autonomic nervous system.drenaline (epinephrine). A hormone of the adrenal medulla which, instilled in the eye, causes a constriction of the conjunctival vessels, dilates the pupil and diminishes the intraocular pressure. See adrenergic receptors; ocular decongestant; naphazoline; neurotransmitter; noradrenaline (norepinephrine).