| Research Abstract |
Superior cervical sympathtic ganglion (SCG) contains many cholinergic synapses, and maintains impulse transmission activity after removal from the rat. When neurotransmitter (acetylcholine ; Ach) was applied to the physiological saline medium during aerobic incubation of the excised SCG,rapid and significant rise in activity of Ca^<2+> -dependent eNzyme, transglutaminase (TG) was observed. Carbachol, a muscarinic ACh agonist, strongly increased the tissue TG activity within minutes, which was fairly antagonized by a muscarinic ACh antagonist, atropine. Nitric oxide (NO), a new transmitter candidate, remarkably accelerated TG activity in the SCG,and the activity was suppressed by a specific inhibitor for NO synthase, N^G -monomethyl-L-arginine. The rate of NO activation was measured byh the formation of cyclic GMP,but the an inhibitor of guanylate cyclase, methylene blue, did not supressed the Carb-induced TG activity increase. These results suggest that Carb -stimulation to the SCG neurons initiate the intracellular signal transfer process for the activation of TG via receptor mediated NO and cyclic GMP increase to cause intracellular Ca^<2+> rise.
|
