Metabolism of Phosphatidyl Inositol and Other Lipids in Active Neurones of Sympathetic Ganglia and Other Peripheral Nervous Tissues. The Site of the Inositide Effect*

Abstract

IT HAS recently been shown that nerve cell activity, induced in an excised sympathetic ganglion by stimulation of its preganglionic nerve, increases the rate of labelling of phosphatidyl inositol by 32P from inorganic phosphate (LARRABEE, KLINGMAN and LEICHT, 1963). The increase in rate of labelling can be as great as two-fold. No increase in labelling was observed in any of the other phospholipids examined, which included phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidic acid, although other investigators have reported that labelling of phosphatidic acid can be increased by stimulating sympathetic ganglia with acetylcholine plus eserine (HOKIN, HOKIN and SHELP, 1960).The purpose of the present experiments was to investigate the locus of the effect of neuronal activity on labelling of phosphatidyl inositol. Was it presynaptic or postsynaptic? Did it occur in dendrites, cell bodies, or axons? Was it related to impulse conduction or to synaptic transmission ?The investigation included a comparison of various ganglia and nerve trunks, the effects of block of ganglionic transmission with tubocurarine, the effects of impulses conducted antidromically into a sympathetic ganglion, and chemical as well as electrical stimulation. M E T H O D SThe majority of the experiments were made on tissues excised from adult white rats, usually females weighing 180-220 g, anaesthetized with urethane. The tissues included superior cervical ganglia in continuity with lengths of preganglionic and postganglionic nerves, cervical sympathetic (preganglionic) nerve trunks, vagus nerve trunks, the non-synaptic (sensory) ganglion nodosum of the vagus nerve, and phrenic nerves. For comparison, a few superior cervical ganglia from mice, hamsters, and rabbits were studied. Before incubation, connective tissue sheaths were removed from the sympathetic ganglia of rats and rabbits, from the preganglionic nerves, and from the vagal ganglia. The sheaths were not removed from phrenic nerves or from the mouse or hamster ganglia.Typical wet weights of the preparations (in /cg) were as follows. Sympathetic ganglia: rat, 820; mouse, 130; hamster, 450; rabbit, 4200. Vagus ganglia from rat, 500. Rat nerve trunks: cervical sympathetic, 70; vagus, 750; phrenic, 940. Ratios of wet weight to dry weight for superior cervical ganglia of rats, determined occasionally during the course of these experiments, averaged 5.2 i 0.1 (mean f s.E.M., N = 9).The tissues were incubated at 37", typically for 4 hrs, in a bicarbonate-buffered physiological solution containing glucose. To this was added inorganic [32P]phosphate, usually about 20 pc/ml, and about 10 /cc/ml of glucose, uniformally labelled with 14C (specific activity at least 60 mc/m-mole). Carrier-free [32P]phosphate was obtained from E. R. Squibb and Sons, and labelled glucose from Nuclear Chicago Corp. or New England Nuclear Corp. The solution was kept in motion around the preparation by continual bubbling of 5 % C02-95 % 02.

Phospholipids in Synaptic Function

“…Synaptosomal localization of the phospholipid effect suggested a relationship with chemical transmission and this view was reinforced by the work of Larrabee and his colleagues on isolated sympathetic ganglia. In this research the preganglionic nerve was stimulated electrically and postganglionic action potentials were recorded (LARRABEE et a/., 1963). Rat superior cervical ganglia were surrounded by oxygenated saline containing suitable radioactive pre-5 cursors and during activity there was an increased labelling of phosphatidylinositol, though not of phosphatidate, phosphatidylcholine or phosphatidylethanolamine.…”

“…Rat superior cervical ganglia were surrounded by oxygenated saline containing suitable radioactive pre-5 cursors and during activity there was an increased labelling of phosphatidylinositol, though not of phosphatidate, phosphatidylcholine or phosphatidylethanolamine. The phosphatidylinositol effect was associated with ganglia and did not accompany conduction of impulses along nerve trunks (LARRABEE & LEICHT, 1965).…”

The association between phosphatidylinositol phosphodiesterase activity and a specific subunit of microtubular protein in rat brain

“…Hormonal stimulation of phosphatidylinositol turnover has been demonstrated in thyroid gland treated with pituitary thyrotrophin (Scott et al, 1968), in rat heart after adrenaline administration (Gaut & Huggins, 1966), and in adipose tissue stimulated with insulin (De Torrentegui & Berthet, 1966). Similar effects have been observed in nervous tissue after electrical stimulation (Larrabee & Leicht, 1965;Pumphrey, 1969) or treatment with acetylcholine (Hokin, 1970). Double-labelling experiments in which radioisotope was incorporated into the glycerol or fatty acid moiety of the phospholipid indicated Vol.…”

Recovery of cholinesterases in soman‐injected superior cervical ganglion of the rat in the presence and absence of innervation

“…It is conceivable that some of the reported multiple modes of action of ACh in sympathetic ganglia [Larabee and Leicht, 1965;Larabee, 1968;Lapetina et al, 1976;Pickard et al, 1977;Greene and Rein, 1978;Ikeno et al, 1981;Ip et al, 1982;Morita et al, 1982;Bone et al, 1984;Bone and Michell, 1985;Briggs et al, 1985;Brown and Selyanko, 19851 may not be primarily linked to the direct activation of subsynaptic nicotinic receptors. Therefore, the presence of cholinesterases (ChEs) on various ultrastructural sites outside of the nicotinic synapses could be expected.…”