Mechanism of splenic contraction produced by severe hypercapnia

¹ Department of Physiology, University of Minnesota, Minneapolis, Minnesota

Unilaterally adrenalectomized and bilaterally adrenalectomized mongrel dogs with both normal and denervated spleen were made hypercapnic by inhalation of 30% CO₂ in oxygen in order to determine the mechanism of the resulting splenic contraction. The results obtained indicate that splenic contraction in dogs breathing 30% CO₂ is mediated by both the splenic nerves and by the adrenal glands. The nerves appear to act more rapidly but contraction still occurs in the absence of all innervation. Neither bilateral adrenalectomy nor splenic denervation alone completely blocked the splenic response in all animals, but of the two procedures the former appeared to be much more effective in this respect. In order to completely block splenic response to inhalation of 30% CO₂, both denervation of the spleen and bilateral adrenalectomy were necessary.