C. Belloli et al., IN-VITRO EFFECTS OF TACHYKININS ON THE SMOOTH MUSCULATURE OF HORSE GUT, Journal of veterinary pharmacology and therapeutics, 17(5), 1994, pp. 379-383
The contractile effects of the tachykinins eledoisin, substance P and
neurokinin A and B were investigated in vitro on circular and longitud
inal muscle strips from horse duodenum, ileum and colon. Circular smoo
th muscle of the small intestine was highly responsive, large intestin
e circular smooth muscle less so, while longitudinal muscle from all g
ut segments was much less sensitive. pD2 values and intrinsic activiti
es on small intestine circular muscle indicated differences in recepto
r distribution between the duodenum and ileum: NK3 and a smaller numbe
r of NK2 receptors being present in the duodenum, and NK2 receptors pr
edominating in the ileum. Notwithstanding this, eledoisin and neurokin
in B were the most active substances on duodenum and ileum, respective
ly. These findings suggest that tachykinins may play a role in equine
gastrointestinal pathophysiology.