The activity of neutral ribonucleases in nuclei of rat sympathetic ganglia and effects of nerve injury.
Nuclei were isolated from homogenates of rat superior cervical ganglion by a conventional differential centrifugation technique with approximately 60% recovery. Ribonuclease activity at pH 7.1 (neutral ribonuclease) was associated with the "nuclei fraction" and represented 19% of the overall activity in normal ganglia. Ribonuclease in the "nuclei fraction" was stimulated variably by the sulfhydryl blocker N-ethylmaleimide indicating that a proportion was bound to the endogenous ribonuclease inhibitor present in these ganglia. The total activity of nuclear ribonuclease was increased 2-6 days after postganglionic nerve injury, such that the inhibitor-bound form of the enzyme increased maximally by 600% at day 4. The percentage of the total ganglionic activity in the "nuclei fraction" decreased in injured ganglia as a result of a rise in the activity of non-nuclear components. The changes in nuclear ribonuclease activity were distinct from those in the 850 g supernatant indicating that specific nuclear enzymes are being affected during regeneration.
D000818:Animals; D002467:Cell Nucleus / Q000201:enzymology*; D005033:Ethylmaleimide / Q000494:pharmacology; D005260:Female; D005728:Ganglia, Sympathetic / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D007700:Kinetics; D009416:Nerve Regeneration; D051381:Rats; D011919:Rats, Inbred Strains; D012260:Ribonucleases / Q000378:metabolism*
D012260:Ribonucleases; D005033:Ethylmaleimide