Electrolyte distribution in rabbit superior cervical ganglion

Abstract— Superior cervical ganglia of the rabbit were removed and analysed for Na⁺, K⁺, Ca²⁺, Mg²⁺ and Cl^?. The mean electrolyte content in μmole/g wet wt. was as follows: Na⁺, 64.7 ± 1.3; K⁺, 65.1 ± 2.7; Ca²⁺, 3.71 ± 0.28; Mg²⁺, 3.70 ± 0.50; and Cl^?, 50.15 ± 2.26. Water content was 0.76 ± 0.01 ml/g wet wt. Extracellular space was 0.37 ± 0.01 ml/g, and the vascular space 0.0238 ± 0.0002. The mean resting potential of the rabbit superior cervical ganglion was – 68.6 mv. After correction for extracellular electrolyte content, the potential differences, E_Na, E_K and E_cl, were estimated to be +33.6 mv, –96.9 mv and -41.1 mv, respectively, in the ganglia. Permeability coefficients for K⁺, Na⁺, and Cl^? were estimated to be 1:0.06:0.02. Replacement of sodium in physiological saline solution by lithium results in a displacement of 94 per cent of the sodium content of the ganglion and 69 per cent of the potassium after 30 min of equilibration.