PHOSPHOINOSITIDE METABOLISM IN RAT SUPERIOR CERVICAL GANGLION, VAGUS and PHRENIC NERVE: EFFECTS OF ELECTRICAL STIMULATION and VARIOUS BLOCKING AGENTS¹

Abstract

Abstract— Paired vagus nerves, phrenic nerves or superior cervical ganglia from rats were incubated at 37 C for various times in a simple salt solution containing glucose and 32 P i . One of the pair was usually stimulated electrically for 30 or 60 min. Stimulation of vagus nerve for 30 min increased phosphate incorporation into all the phospholipids studied but the increase was significant only in the case of triphos‐phoinositide and diphosphoinositide. This increase was not accompanied by increased labelling of the nucleotide labile phosphate pool. Tetrodotoxin at concentrations sufficient to block transmission had no effect upon phospholipid labelling in vagus or phrenic nerve. Ouabain at blocking concentration did not affect polyphosphoinositide metabolism in vagus nerve but increased [ 32 P]labelling of the other phospholipids. Hemicholinium‐3 increased the labelling of all three phosphoinositides in the sympathetic ganglia but the increase in phosphatidylinositol labelling due to electrical stimulation was not seen in the presence of this inhibitor.