ABSTRACT
Transmembrane potentials of myenteric ganglion cells were recorded intracellularly with glass micropipettes filled with 3 M potassium chloride and having tip resistances of 50 to 80 megohms. Synaptic potentials, and antidromic or orthodromic action potentials, were evoked in impaled neuronal somas by focal electrical shocks applied to interganglionic connective fibers with platinum-wire electrodes and an electronic stimulator. Neurons were exposed to pharmacological agents, neurotransmitter substances and a saline-extracted somatic protein antigen from Trichinella larvae by addition to the physiological salt solution perfusing the recording chamber, and ejection from pipettes onto the ganglionic surface. Histamine induced prolonged bursts of spontaneous action potentials in 9 neurons recorded from myenteric plexus preparations from Trichinella infected animals. Exposure of myenteric ganglion cells to a saline-extracted somatic protein preparation from Trichinella larvae enhanced membrane excitability and altered nicotinically-mediated fast synaptic transmission only in neurons from immune animals.
