Using ultrasound to understand vascular and mantle contributions to venous return in the cephalopodSepia officinalisL.

Abstract

SUMMARY Using ultrasound imaging, we investigated the roles of the potentially contractile veins and of the mantle (the powerful body wall that moves water over the gills, and also encloses the large veins and the hearts) in returning the blood of cuttlefish to its hearts. Ultrasound provided the first non-invasive observations of vascular function in an unanaesthetized,free-moving cephalopod. The large veins (anterior vena cava, lateral venae cavae and efferent branchial vessels) contracted in live, intact cuttlefish(Sepia officinalis L.). The anterior vena cava contracted at the same rate as the mantle, but it often expanded during mantle contraction. Furthermore, the anterior vena cava contracted peristaltically in vivo, suggesting that it actively aids venous return. The lateral venae cavae and efferent branchial vessels contracted at the same rate as the branchial and systemic hearts, but at a different rate from the mantle. A peristaltic wave appeared to travel along the lateral venae cavae to the branchial hearts, potentially aiding venous return. We found a muscular valve between the anterior and lateral venae cavae, which ensured that blood flowed only one way between these unsynchronized vessels. The mantle appears to have an unclear connection with cardiovascular function. We conclude that, when cuttlefish are at rest, the mantle does not compress any of the large veins that we imaged (including the anterior vena cava), and that peristaltic contractions of the large veins might be important in returning cephalopod blood to the hearts.

Effect of Different Formulations of Magnesium Chloride Used As Anesthetic Agents on the Performance of the Isolated Heart of Octopus vulgaris

“…The fall in haemolymph flow to the brain together with the marked reduction of ventilation is likely to lead to ischaemia of the brain (and other tissues) that could contribute to the anesthetic state induced by the various magnesium chloride formulations. Direct effects of the magnesium chloride formulations on the heart are likely to be compounded by the suppression of ventilation and muscular activity of the arms caused by anesthesia which contribute to venous return (Wells, 1983; King et al, 2005). In addition, acute hypoxia is itself associated with bradycardia and reduced aortic flow in cephalopods, as reported, for example, for Nautilus pompilius (Boutilier et al, 2000) and O. vulgaris (Wells, 1983).…”

Non-invasive study ofOctopus vulgarisarm morphology using ultrasound

“…Ultrasonography has already been applied on cephalopods to examine internal structures, like inside the mantle (Davenport, 1993;King et al, 2005;King and Adamo, 2006) or the brain (Grimaldi et al, 2007). Ultrasound is thus confirmed to be a powerful tool that allows investigation of the behavior, physiology and biomechanics of the arm in the living animal, by a non-invasive method.…”

The Digestive Tract of Cephalopods: Toward Non-invasive In vivo Monitoring of Its Physiology

“…Ultrasonographic examination can be undertaken without sedation or anesthesia as carried out in S. officinalis (King et al, 2005; King and Adamo, 2006) or in O. vulgaris (Grimaldi et al, 2007). However, in other circumstances light anesthesia is required to ensure stable images for quantitative analysis of arm or brain morphology (Grimaldi et al, 2007; Margheri et al, 2011).…”