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One of the characteristic effects of pseudo-rabies virus infection in the superior cervical ganglion of the rat is the occurrence of spontaneous nerve impulses. They are discharged periodically over both preganglionic and post-ganglionic trunks, orthodromically in the post-ganglionic, and antidromically in the preganglionic trunk (Dempsher, Larrabee, Bang & Bodian, 1955).In order to explain this spontaneous activity, it was assumed that following infection with pseudo-rabies virus a state of hyperexcitability develops at the presynaptic nerve endings which enables impulses to be generated in a few presynaptic nerve endings. This leads to excitation of the ganglion cells, as well as to an abnormal retrograde spread of excitation over the preganglionic fibres (Dempsher et al. 1955). Evidence supporting the view that the spontaneous impulses discharged over pre-and post-ganglionic tissues of virusinfected ganglia have their origin in presynaptic nerve terminations, was obtained by suppressing the activity in the post-synaptic neurones, and demonstrating that the activity continued in the presynaptic nerve.The experiments described in this paper confirm this hypothesis and they suggest that spontaneous release of acetylcholine (ACh) at presynaptic terminations plays a role in the spread of activity over both nerve trunks. The experiments deal with the effects of preganglionic denervation, of calcium removal, of tubocurarine, acetylcholine, and physostigmine on the spontaneous activity in infected ganglia. METHODSThe methods, which have been described in detail by Dempsher et al. (1955), were essentially as follows: Rat superior cervical ganglia were infected following intraocular inoculations of a 10% suspension of pseudo-rabies-infected chorio-allantoic membranes of 10-to 12-day-old chick embryos. The ganglia were excised at a desired stage of infection and suspended upon platinum

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Bis(quaternary ammonium) compounds in which one or both quaternary nitrogens bear iodinated benzyl moieties and the charged centers are separated by 2, 4, 6, or 10 methylene units have been synthesized and evaluted for (a) binding to cartilaginous material, (b) radiocontrast characteristics, and (c) in vitro pharmacological effects. Also prepared was 1,5-diiodo-2,4-bis(beta-trimethylammonioethyl)benzene diiodide, an analogue in which the iodinated aryl group lies between the charged nitrogen centers. Biological studies show that these compounds bind to cartilage but at relatively slow rates and with low persistence, resulting in low and transient levels of radiopacity. In common with simpler bisquaternary compounds, these compounds block synaptic transmission.

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