IL6 and hereditary pheochromocytoma-paraganglioma: Increases acetylcholinesterase, choline acetyltransferase, superoxide dismutase (SOD) and catalase (CAT) activities and acetylcholine, glutathione (GSH) and IL-4 levels, and decreases IL-1β, IL-6 and TNF-α levels in a cell line that was derived from a transplantable rat pheochromocytoma (seed coat extracts of P. × suffruticosa)