A 3-dimensional analysis of modes of cardiovascular adaptation: concepts, methods and preliminary findings.

OBJECTIVE: To present a 3-dimensional approach to displaying and interpreting processes of cardiovascular adaptation. DESIGN: Laboratory study of blood pressure changes in response to a protocol set in advance. The authors plotted the coordinates of 3711 cardiovascular change events (CVCEs) in 3-dimensional space defined by changes in systolic blood pressure, diastolic blood pressure and heart rate. This was followed by cluster analyses and preliminary estimates of reliability and construct validity. SETTING: The teaching hospitals of a large southwestern US medical centre. PARTICIPANTS: Approximately 100 female nursing personnel aged 25 to 50 years. INTERVENTIONS: Medical history, self-administered questionnaires, laboratory protocol of pressor challenges, rest periods. RESULTS: Nine distinct clusters ("species of response") were identified and replicated in randomly chosen halves of the sample. Postural, isomorphic and psychologic challenges generated several distinctive profiles of "rising" responses, and were also followed by distinctive "declining" responses. The frequencies of various cardiovascular reactions ("clusters") to the same protocol were correlated with psychosocial characteristics and hypertension risk indicators. CONCLUSIONS: The 3-dimensional approach reveals many features of cardiovascular adaptation not discernible from traditional univariate displays and analyses. This paradigm might prove useful for matching patients with hypertension by their cluster patterns to their most suitable medication, but it requires further validation by direct hemodynamic measurements.

Hemicholinium-3 binding: correlation with high-affinity choline uptake during changes in cholinergic activity.

The binding of hemicholinium-3 was measured in the cerebral cortex, hippocampus, and striatum after treatment with cholinergic agonists and antagonists in order to examine its utility as an index of presynaptic cholinergic regulation. The binding of muscarinic receptors and the high affinity uptake of choline were examined in the same tissue. Subacute treatment with physostigmine or arecoline decreased all three parameters, while they were increased by treatment with atropine. The binding of hemicholinium-3 correlated significantly with the high affinity uptake of choline. It may therefore be a useful reflection of this phase of cholinergic regulation, under conditions where measurement of the uptake of choline is not feasible, including autoradiographic and post mortem studies.

High-affinity hemicholinium-3 binding to brain membranes: reduction by treatment with physostigmine in vivo.

We examined high-affinity, sodium-dependent binding of hemicholinium-3 to brain membranes. Binding, with Kd of about 3 nM, was highest in corpus striatum, intermediate in cerebral cortex and hippocampus, and low in cerebellum. Treatment with physostigmine in vivo reduced binding in all regions without affecting apparent affinity.