Relations between blood pressure and plasma norepinephrine concentrations after administration of diltiazem to rats: HPLC‐peroxyoxalate chemiluminescence determination on an individual basis

Abstract

A calcium antagonist, diltiazem, was infused continuously into Sprague-Dawley rats through the left femoral vein at four different flow rates. The mean arterial blood pressure and concentrations of plasma norepinephrine (NE) were measured in each single rat (n = 5) and the correlations between them were studied. Blood (150 microL) was collected 13 times during the infusion. Plasma NE was determined by HPLC-ethylenediamine condensation reaction-peroxyoxalate chemiluminescence detection system (HPLC-ED-PO-CL). In four cases from 5 rats, the blood pressure reduction caused by diltiazem was inversely correlated to logarithm of plasma NE concentration. The relation was expressed as Y = -alogX+m. The coefficients of correlation were -0.9506, -0.9293, -0.9341 and -0.8675, respectively. The correlation for the last rat was worse (r = -0.0799). The good correlation would imply that the sympathetic nervous system released NE to maintain blood pressure up to the normal level, responding to the sympathetic nervous system released NE to maintain blood pressure up to the normal level, responding to the blood pressure reduction caused by diltiazem. The present experiment proved the feasibility of the determination method of NE utilizing HPLC-ED-PO-CL detection in applying to the individual rats.

Changes of plasma l-arginine levels in spontaneously hypertensive rats under induced hypotension

“…In our present work as well as previous studies Higashidate et al, 1994;Imai et al, 1994) with SD Imai et al, 1994) and SH and WKY rats , we observed the quantitative correlation between an increase in plasma NE concentration and blood pressure reduction. This is presumably because the SNS released NE to maintain blood pressure up to normal levels responding to the blood pressure reduction caused by nicardipine.…”

Reduced Membrane-Bound Catechol-O-Methyltransferase in the Liver of Spontaneously Hypertensive Rats

“…For example, hypotensive responses caused by calcium antagonists in rats have been shown to correlate with the increases of plasma NE concentrations. Furthermore, we previously reported that the response was reduced in spontaneously hypertensive rats (SHR) as compared with that in normotensive Wistar-Kyoto (WKY) rats (3)(4)(5)(6).…”

An Invitation to Bio-Analytical Chemistry

“…3). 6 The more dull sympathetic nervous activity in the hypertensive rats (spontaneously hypertensive rats, SHR) as compared with that in the normotensive (Wistar Kyoto, WKY) rats was also clarified (Fig. 4).…”

“…5 As described above (3·1), the trace analysis of blood catecholamines clarified the relation between the blood pressure and the sympathetic nervous system. 4,[5][6][7][8]47 …”