THE SHIVERING RESPONSE DURING CROSS-CIRCULATION IN THE COMMON EIDER DUCK (SOMATERIA-MOLLISSIMA)

The possible role of humoral factors in the control of shivering in th e common eider duck (Somateria mollissima) was investigated using a cr oss-circulation technique. Pairs of animals were coupled so that the a rterial system of one animal was connected to the venous system of the other. The rate of blood transferral was 12.8 ml min-1. By adequate h eparinization of the extracorporeal blood supply, cross-circulation co uld be maintained for periods of up to 12 h. The temperature of blood entering each animal (T(inlet)) was controlled by heat exchangers. Dur ing control experiments T(inlet) was maintained at a temperature close to normal body temperature. During cooling experiments T(inlet) was m aintained at c. 20-degrees-C. Changes in metabolic heat production and oesophageal temperature in response to blood cooling were measured in cross-circulated pairs of animals cooled simultaneously or individual ly. Based on analysis of the metabolic responses under the different e xperimental situations, no evidence was found to indicate that blood-b orne substances are involved in the shivering response in these animal s.