Excitatory and neurotoxic actions of platelet-activating factor on rat myenteric neurons in cell culture.

At micromolar concentrations, PAF causes intense excitation and elevation of intracellular Ca in a subset of myenteric neurons. When applied for more than about 10 seconds, these concentrations of PAF kill a subset of myenteric neurons. The excitation and elevation of Ca levels are accompanied by increased membrane conductance and enhanced synaptic activity. The effects of brief applications are reversible, but responses to subsequent applications of PAF are substantially reduced. If such responses can be elicited in enteric neurons by the concentrations of PAF that are generated in vivo, they would account for the potent ability of PAF to evoke neurally-mediated secretory responses in GI tissues.