Local blood flow and metabolism of the tongue before and during panting in the dog


The effects of hyperthermia on blood flow and oxygen consumption $$(\dot V_{O_2 } )$$ of the tongue were investigated in anesthetized dogs. For comparison, blood flow through the skin and deep muscle of the hind leg was also measured in some animals. Increasing blood temperature revealed a biphasic response of lingual blood flow. At 41°C blood temperature respiratory frequency was twice that of control and there was a reduction of lingual blood flow, while resistance of the lingual bed was increased significantly. The arterio-venous oxygen difference (AVDO2) of lingual blood was markedly increased at this level and the $$\dot V_{O_2 } $$ of the tongue was like-wise significantly greater than control. At 41.9°C, the steep increase of respiratory frequency was accompanied by a marked fall in lingual resistance as evidenced by a four-fold increase of lingual blood flow. The systemic AVDO2 rose at this temperature, while the lingual AVDO2 fell dramatically. There was no further increase of lingual $$\dot V_{O_2 } $$ . At both temperature levels the blood flow through the skin did not change substantially, while the deep muscle blood flow slightly increased. The mean arterial pressure showed a progressive fall during hyperthermia. It is assumed that the decrease of lingual blood flow at elevated blood temperature without panting is due to a redistribution of cardiac output to areas other than the tongue. The increase of lingual blood flow without an additional increase of lingual $$\dot V_{O_2 } $$ during panting may be explained solely as a mechanism for heat dissipation. The fact that the decrease of lingual resistance was demonstrated in immobilized animals concomitant with high frequency phrenic burst activity suggests that the decrease of lingual resistance and panting may be induced by a common central integrating mechanism.

DOI: 10.1007/BF00586842

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@article{Kindermann1973LocalBF, title={Local blood flow and metabolism of the tongue before and during panting in the dog}, author={Wilfried Kindermann and Klaus Pleschka}, journal={Pfl{\"{u}gers Archiv}, year={1973}, volume={340}, pages={251-262} }