DEFINITION of 'Commercial'. Relating to commerce. In the investment field, the term commercial is generally used to refer to a trading entity engaged in business activities that are hedged by positions in the futures or options markets.
The melanocortin 1 receptor controls which type of melanin is produced by melanocytes. When the receptor is activated, it triggers a series of chemical reactions inside melanocytes that stimulate these cells to make eumelanin. If the receptor is not activated or is blocked, melanocytes make pheomelanin instead of eumelanin.
Melanocytes synthesize and store brown pigment, melanin, that gives  the tissue a dark color. Melanocytes are common in the stratum  basale of the epidermis in the skin, wheâ¦re they play a major role  in determining skin color. They are also found in the dermis, eye,  heart, brain, and bone..