Postmortem changes in rat brain: studies on membrane-bound enzymes and receptors.

Abstract

The relationship between the stability of potential neurochemical markers and autolysis time was studied at 4 degrees C and 25 degrees C using postmortem brain samples from two rat strains. In general, qualitatively similar results were obtained with either N/Nih or Sprague-Dawley rats; however, quantitative differences were often observed, particularly in regard to benzodiazepine receptor changes. For every enzyme activity or binding property examined, no significant change was found when brains were kept at 4 degrees C for up to 72 h prior to freezing at -70 degrees C. Na,K-ATPase and low-affinity Ca-ATPase activities were also stable in brains kept at 25 degrees C for up to 72 h. Mg-ATPase activity was reduced in brains kept at 25 degrees C for 24 and 48 h. [3H]Guanidinoethylmercaptosuccinic acid [( 3H]GEMSA) binding to enkephalin convertase in the cytosol was not significantly changed in brains kept at 25 degrees C; however, a small increase was seen for [3H]GEMSA binding to the membrane fraction at 24, but not 48 and 72 h postmortem. [3H]Quinuclidinyl benzilate [( 3H]QNB) binding to muscarinic cholinergic receptors decreased in brains kept at 25 degrees C for 72 h. Opioid receptor binding also decreased in brains kept at 25 degrees C. Using [3H]2-D-alanine-5-D-leucine enkephalin to label delta opioid receptors, a statistically significant decrease in binding was observed as early as 6 h postmortem, and was completely abolished after 72 h at 25 degrees C. In contrast, [3H]naloxone binding was unchanged after 24 h at 25 degrees C, but was decreased after 48 and 72 h.(ABSTRACT TRUNCATED AT 250 WORDS)

• Authors: P J Syapin, T Ritchie, L Noble, E P Noble
• Journal: Journal of neurochemistry (J Neurochem) Vol. 48 Issue 4 Pg. 1285-90 (Apr 1987) ISSN: 0022-3042 [Print] England
• PMID: 3029332 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Receptors, GABA-A
• Receptors, Neurotransmitter
• Receptors, Opioid
• Succinates
• Naloxone
• Enkephalin, Leucine
• Enkephalin, Leucine-2-Alanine
• Quinuclidinyl Benzilate
• guanidinoethylmercaptosuccinic acid
• Ca(2+) Mg(2+)-ATPase
• Calcium-Transporting ATPases
• Sodium-Potassium-Exchanging ATPase
• Diazepam

Topics

• Animals
• Brain (enzymology, metabolism)
• Ca(2+) Mg(2+)-ATPase (metabolism)
• Calcium-Transporting ATPases (metabolism)
• Cell Membrane (enzymology, metabolism)
• Diazepam (metabolism)
• Enkephalin, Leucine (analogs & derivatives, metabolism)
• Enkephalin, Leucine-2-Alanine
• Female
• Male
• Naloxone (metabolism)
• Postmortem Changes
• Quinuclidinyl Benzilate (metabolism)
• Rats
• Rats, Inbred Strains
• Receptors, GABA-A (metabolism)
• Receptors, Neurotransmitter (metabolism)
• Receptors, Opioid (metabolism)
• Sodium-Potassium-Exchanging ATPase (metabolism)
• Succinates (metabolism)