The stability of angiotensin receptors and angiotensin converting enzyme in post mortem brain

Quantitative in vitro autoradiography was used to assess the post mortem stability of angiotensin II receptors and angiotensin converting enzyme in adult sheep brainstems. There was no significant loss of angiotensin II receptor binding in brainstems stored for up to 24 h at 23 degrees C or for 8 h at 23 degrees C followed by 64 h at 4 degrees C. There was no significant decrease in angiotensin converting enzyme binding in the same nuclei after up to 48 h at 23 degrees C or after 8 h at 23 degrees C followed by up to 64 h at 4 degrees C. Interpretation of neurochemical studies of human brain tissue obtained at autopsy requires assessment of the post mortem stability of the molecules being studied. Our results indicate that angiotensin II receptors and angiotensin converting enzyme are remarkably stable in sheep brainstems after post mortem delays in excess of those usually encountered in hospital autopsies.