Effects of modifications of gastric motility on the membrane potential of the coeliac ganglionic neurons in the rabbit

The involvement of gastric motility in the slow variations of membrane potential of sympathetic ganglionic neurons was investigated in rabbit. The present study was performed in vitro on the coeliac plexus connected to the stomach. The electrical activity of ganglionic neurons was investigated using intracellular recording techniques. Spontaneous increases in basal intragastric pressure triggered slow hyperpolarizations of the ganglionic neurons (n = 7), the duration of which was similar to that of the increase in the basal pressure. Conversely, cooling of the nerve trunks connecting the coeliac plexus to the stomach induced a slow depolarization of the ganglionic neurons (n = 3). Carbachol-induced increases in basal intra-gastric pressure modified the membrane potential of ganglionic neurons in several ways: hyperpolarization (n = 6), depolarization (n = 4), hyperpolarization followed by depolarization (n = 2), and these modifications lasted longer than the modifications of gastric motility. After cooling of the nerve trunks connecting the coeliac plexus to the stomach, the carbachol-induced variations of gastric motility were no longer able to modify the membrane potential of the ganglionic neurons. These results demonstrate that modifications of the gastric motility can trigger slow modifications of the resting membrane potential of coeliac neurons and therefore could modify their excitability. This suggests that gastric motility can modify at the postsynaptic level the transmission of central or peripheral inputs to ganglionic neurons.     

17O n.m.r. studies of amino acids in the solid state,in single- and polycrystalline forms

A single crystal of ¹⁷O enriched α-glycine was grown by slow evaporation of aqueous solution. ¹⁷O n.m.r. studies of the α-glycine molecule in single crystalline form revealed five ¹⁷O transitions each consisting of two lines due to inequivalency of the oxygen atoms in the unit cell, with each of these lines revealing a dipolar interaction between the ¹⁷O and the nearest hydrogen atom. The spectral width was found to be of the order of magnitude of MHz and the linewidths of the order of magnitude of 2 kHz.     

ULTRASTRUOTURAL STUDY OF SKELETAL MUSCLE IN MORPHOEA

SUMMARY.— Electron microscopic studies have been carried out in 2 cases of localized and one of generalized morphoea. Specimens were taken from pectoralis major, trapezius, quadriceps femoris and biceps brachii in areas of affected skin. The muscle fibre and its components showed various degrees of damage—vacuolization, absence of some bands and focal or marginal atrophy of some myofibrils. Band Z was the most resistant. No changes were seen in muscle capillaries. In both forms of morphoea the sarcoplasmic reticulum in some muscle fibres was widened at the expense of myofibrils. In both conditions some muscle fibres and their components were unaffected.