Nitric oxide: a vasodilatatory mediator in the cephalic aorta of Sepia officinalis (L.) (Cephalopoda).
Evidence is presented that nitric oxide (NO) may regulate blood pressure in cephalopod molluscs. In vitro tests performed on the cephalic aorta of Sepia officinalis (L.) (Cephalopoda) showed that the NO releasers (glyceroltrinitrate, sodium nitroprusside, 3-morpholinylsydnoneimine chloride and KNO(2)) induced concentration-dependent vasodilatation of vessel segments (without the tunica adventitia/periadventitia) precontracted by dopamine. These vasodilatatory actions could be totally blocked by oxadiazolo[4,3-a] quinoxalin-1-one, an inhibitor of the NO-sensitive guanylyl cyclase, and partially mimicked by the cyclic guanosine monophosphate (cGMP) analogue 8-bromo cGMP and by the phosphodiesterase inhibitor, zaprinast. The NO-precursor, L-arginine, showed vasodilatatory effects only on segments of the aorta in which the layers containing nerves (tunica adventitia/periadventitia) had been left intact, suggesting that NO synthase may be located within peripheral nerves.
Schipp
R
R
Institut für Allgemeine und Spezielle Zoologie der Justus-Liebig-Universität, Giessen, Germany.
Gebauer
M
M
D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000502:physiology; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006162:Guanylate Cyclase / Q000378:metabolism; D008297:Male; D008974:Mollusca / Q000502:physiology*; D009569:Nitric Oxide / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009924:Organ Culture Techniques; D011493:Protein Kinase C / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology*
D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D014665:Vasodilator Agents; D009569:Nitric Oxide; D011493:Protein Kinase C; D006162:Guanylate Cyclase; D006152:Cyclic GMP