The islet organ of the Atlantic hagfish, a cyclostome, phylogenetically is the most original islet parenchyma. It is well equipped with blood vessels, but lacks nerves. The aim of the present study was to evaluate the relative proportions between regional blood flows in these animals with a microsphere technique and with laser-Doppler flowmetry. As regards the results obtained in the kidneys, gills, and islet organ, the data were essentially the same found using both methods. Approximately 20% of the injected microspheres were found in the kidneys; when corrected for weight, the gill bodies and the islet organ were also found to have the same blood perfusion. The blood flow to the brain and that of the gut and the liver were only approximately 30% and 10%, respectively, of that to the kidney. Topical application of the nitric oxide donor, sodium nitroprusside failed to affect the islet blood flow. Apart from this observation, this non-innervated “primitive” islet parenchyma did not differ from that of the amply innervated mammalian islets with regard to their high basal blood perfusion.
Key words
Cyclostomian Islets of Langerhans - Microspheres - Laser-Doppler Flowmetry - Blood Flow - Nitric Oxide
