3H-Nicotine in cat superior cervical and nodose ganglia after close-arterial injection in vivo

Abstract

1 Concentrations of ³H-nicotine in the superior cervical and nodose ganglia of anaesthetized cats were measured after close-arterial injection. 2 Shortly after injection there was a higher concentration of ³H-nicotine in the superior cervical ganglion than in the nodose ganglion. Mean concentration ratios, superior cervical ganglion/nodose ganglion (S/N ratios) were: 2 min after injection, 1.60 ± 0.19; 4 min, 1.21 ± 0.19; 8 min, 0.92 ± 0.05. These ratios were independent of the dose of nicotine over the range 4 to 200 μg in 0.2 ml. 3 There was no comparable difference in the concentrations of injected ¹⁴C-inulin or ³H₂O in the two ganglia, or in total water content. 4 Procedures which reduced the pharmacological action of nicotine (pre-treatment with hexamethonium, admixture of ¹⁴C-inulin) tended to reduce the S/N ratio for nicotine. 5 Autoradiographs showed that nicotine entered the neurones of both superior cervical and nodose ganglia. 6 It was concluded that the higher concentration of nicotine in the superior cervical ganglion was probably related to its selective pharmacological action at this site, and may have been due to a greater intracellular retention of nicotine.