aforementioned novel neuropeptides. Aptly named Substake K (SK) and neuromedin K (NMK) due to structural homology with kassinin, the pharmacological effects also establish these as major player in mammalian systems, with SK having only 1/3rd the effect on SP-P specific receptors while SP-E receptors in rat vas deferense experienced a 300x greater effect upon binding SK. With only 3 tachykinins having been studied, it was the study of kassinin that allowed these emprical comparisons to be made. As a research tool Novel discovery of new mammalian tachykinins similar to amphibian Kasshinin led to an interest in postulating kassinin's direct action on mammalian CNS. Kassinin injections administered to rats upon subjecting their cells to dehydration due to high salt content, led to the discovery that the neuropeptide inhibits thirst despite the cellular dehydration for up to several hours. Throughout the duration of study, sodium excreted through urine is also low in concentration, and given that the amount of water intake after 6 hours is not sufficient to restore osmotic balance, scientists hypothesize that kassinin triggers an osmotic exchange between intra and intercellular components to maintain water potential. Whether this is due to a CNS modification in the homeostatic regulation of cecllular osmosis is undetermined. While kassinin is not synthesized in the human CNS nad PNS, it has been reported via exposure to external elements and can hence be considered a component of the human exposome, which, given the greater extent of homology in human and rate genome justified to growing interest in the neuropeptide. References Peptides