Substance K, a novel tachykinin injected bilaterally into the ventral tegmental area of rats increases behavioral response

Novel tachykinins such as substance K and neuromedin K have been identified in the mammalian CNS. Bilateral injections of substance K and related peptides as well as of substance P into the dopamine cell body area of the ventral tegmental area caused dose-dependent increases in locomotor activity and rearing, in rats. As this behavior was blocked by the pretreatment with haloperidol (0.1 mg/kg, i.p.), the activation of dopaminergic systems may be involved in the hypermotility induced by the administration of substance K.