sentences:  Since tachykinins were discovered, they have been shown to possess biological activity in number of pathological and physiological systems.Nevertheless, the therapeutic potential of the tachykinin antagonists has not been fully understood.In 2009, it was found that the NK1R gene is transcribed in four mRNA variants, which at the same time are translated into four NK1R isoforms that have different affinities to substance P (known to play a main role in lowering stress response when working on these receptors).