C. Bjenning et al., NEUROPEPTIDE-Y POTENTIATES CONTRACTILE RESPONSE TO NOREPINEPHRINE IN SKATE CORONARY-ARTERY, The American journal of physiology, 265(2), 1993, pp. 80000661-80000665
The skate is an extant representative of the first vertebrate group wi
th a coronary circulation, the elasmobranch fish. Histochemical studie
s have revealed that skate coronary arteries are innervated by adrener
gic nerves as well as by nerves showing neuropeptide Y (NPY)-like immu
noreactivity. This study investigates the effect of NPY in the coronar
y system of an elasmobranch fish, a vertebrate that first evolved 450
million years before mammals and the mammalian coronary circulation. T
he responses of vascular ring preparations of the coronary artery from
the longnose skate (Raja rhina) were measured using isometric force t
ransducers. The main effect of NPY was a potentiation of the amplitude
of the norepinephrine-induced contraction, leaving the pD2 value (-lo
g 50% effective concentration) for norepinephrine unaffected. NPY per
se occasionally contracted the coronary rings in higher concentrations
. The potentiation response may not involve the endothelium and was ab
olished by pretreatment with tetrodotoxin. We conclude from this study
that NPY potentiates norepinephrine-induced contraction in skate coro
nary artery via an indirect pathway.