Premium
Intracellular pH in rat isolated superior cervical ganglia in relation to nicotine‐depolarization and nicotine‐uptake
Author(s) -
BROWN D. A.,
HALLIWELL J. V.
Publication year - 1972
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1972.tb08088.x
Subject(s) - hexamethonium , depolarization , intracellular , chemistry , intracellular ph , nicotine , extracellular , biophysics , stimulation , biochemistry , endocrinology , medicine , biology , receptor
Summary1 The intracellular pH (pH i ) of rat isolated superior cervical ganglia incubated in normal Krebs solution (pH o = 7·37) was estimated to be 7·33 from the uptake of a weak acid, 14 C‐5,5‐dimethyloxazolidine‐2,4‐dione (DMO). Addition of 30 μ m nicotine for 30 min reduced the DMO‐estimated pH i by 015 units to 7·18. This effect was prevented by hexamethonium (2·5 m m ) or by depolarizing the ganglion with K + (124 m m ). 2 3 H‐Nicotine (30 μ m ) was concentrated within the ganglia to an intracellular/extracellular concentration ratio (C i /C o ) of 5·54 in normal Krebs solution and 4·61 in 2·5 m m hexamethonium. This would suggest an intracellular pH of 6·54 and 6·63 respectively. In ganglia previously depolarized by K + the corresponding values for C i /C o were 402 (minus hexamethonium, estimated pH i 6·95) and 4·17 (plus hexamethonium, estimated pH i 6·94). 3 A multicompartment cell interior comprising an acid cytoplasm (pH˜6·6) and more alkaline nucleus and mitochondria is proposed to explain the difference between the values of pH i estimated from the uptake of DMO and nicotine. It is suggested that the fall in pH i during nicotine‐depolarization results from metabolic stimulation following Na + entry.