CHOLINERGIC MODULATION OF IMMUNOGLOBULIN SECRETION FROM AVIAN PLASMA-CELLS - THE ROLE OF CYCLIC MONONUCLEOTIDES

The chicken Harderian (lacrimal) gland contains an abundance of plasma cells in the interstitium of the gland that secrete IgG, IgM, and IgA . In in vitro preparations of this gland, the cholinergic agonist carb achol causes a transient increase in the secretion rate of IgG above a basal level of secretion. We have investigated the effects of the cyc lic mononucleotides cAMP and cGMP on this secretagogue response. Pretr eatment with 20 mu M forskolin or 1 mM dibutyryl cAMP abolished the ca rbachol-induced secretory response. When the gland was isolated in nor mal media and then treated with either forskolin or dibutyryl cAMP, th ere was no change in the baseline secretion rate, cGMP at either 10 mu M or 1.0 mM did not affect the baseline secretion rate, nor did it ha ve an effect on the carbachol response. We postulate that muscarinic r eceptor activation leads to a calcium influx that in turn leads to an increased secretion rate of IgG. The opposing effects of elevating cAM P and cGMP are discussed in the context of this model of cholinergic a ctivation of avian plasma cells.