Arterial Pressure In Cats Research Articles

Synthesis of 1-alkyl-3,4-dihydroisoquinoline derivatives and study of their effect on arterial pressure

A series of 1-alkyl-3,4-dihydroisoquinolines and the related 4-alkyl-1,2-dihydro-benzo[f]isoquinolines was synthesized using reactions of dialkylbenzylcarbinols and their naphthyl analogs with alkylcyanides. Experiments showed that 1-alkyl-6,7-dimethoxy-3,4-dihydroisoquinolines typically produce a hypotensive action, while the benzo-annelated structures usually exhibit a hypertensive effects. The most active compound decreases the arterial pressure in cats by 52 Torr and the effect lasts for about 4 hours.

Evaluation of an oscillometric blood pressure monitor on anesthetized cats and the effect of cuff placement and fur on accuracy.

(1) To determine the usefulness of one specific oscillometric monitor for making indirect measurements of arterial pressure in cats. (2) To determine the difference between two specific cuff placement sites. (3) To determine if clipping the hair beneath the cuff has an affect on the accuracy of oscillometric blood pressure determination. Prospective study comparing the accuracy of the Datascope Passport (Datascope Corp, Paramus, NJ) with concurrent invasive measurements. Six anesthetized domestic felines weighing 4.5 to 5 kg. The direct arterial pressure was measured using a cannula placed in the right common carotid artery. Oscillometric cuffs of appropriate size were placed on both thoracic limbs distal to the elbow and both pelvic limbs distal to the stifle. The hair in the areas of cuff placement on the right limbs was clipped circumferentially. Measurements of systolic, diastolic, and mean arterial pressure (MAP) were taken for each site during normotension, hypotension, and hypertension. Comparisons between indirect and direct measurements were made using a parametric analysis of method comparison. No significant differences were noted when the clipped limbs were compared with the corresponding limbs which were left unclipped (P > .378) or when the thoracic limb measurements were compared with those of the pelvic limb (P > .088). There were significant differences (P < or = .002) between the two pressure measurement methods for the systolic, diastolic, and mean arterial pressures over all three pressure ranges. The Datascope Passport did not accurately estimate the invasively measured arterial pressure. Use of noninvasive blood pressure monitoring equipment is increasing in use in veterinary medicine, and the accuracy of one specific monitor is reported.

Effects of certain vasoactive agents on the long-term pattern of blood pressure, heart rate, and motor activity in cats

Abstract Objective To determine whether a diurnal pattern exists in cardiovascular variables and motor activity, and whether pharmacologic agents that decrease (angiotensin converting enzyme inhibitor) or increase (Nω-nitro-L-arginine methyl ester [L-NAME]) blood pressure alter the pattern. Animals 6 clinically normal cats. Procedure Radiotelemetric implants were used to measure systemic arterial pressure, heart rate, and motor activity in conscious cats maintained in cages. Measurements were obtained during absence of treatment (control), treatment with dietary salt restriction plus an inhibitor of angiotensin converting enzyme (2.5 mg of lisinopril, PO, daily) and treatment with an inhibitor of nitric oxide production (0.1% L-NAME in the drinking water). Results A diurnal pattern in arterial pressure and motor activity was observed, with highest values obtained during presence of laboratory personnel. Mean values for arterial pressure obtained during light hours varied from those obtained during darkness (P &lt; 0.05), but by &lt; 3 mm of Hg. Dietary sodium restriction did not have an appreciable effect on arterial pressure, but the combined administration of a low sodium diet plus lisinopril decreased (P &lt; 0.05) measured indices of arterial pressure. Administration of L-NAME increased arterial pressure (P &lt; 0.05) and altered its diurnal pattern. Conclusions Although a diurnal pattern of arterial pressure was observed, variations were mostly associated with presence of human beings. Administration of L-NAME, but not lisinopril, altered this diurnal pattern. Clinical Relevance Factors that modify arterial pressure may alter the diurnal pattern of cardiovascular variables. In measuring arterial pressure in cats, the effects of human contact may artifactually increase such variables. (Am J Vet Res 1997;58:647–652)

Pial arterial pressure in cats following middle cerebral artery occlusion. II. Relationship to regional disturbance of energy metabolism.

Focal cerebral ischemia was produced in 16 cats by occluding the left middle cerebral artery (MCA) for 120 min. Cortical blood flow and pial artery pressure were determined prior to vascular occlusion and after 15, 60 and 120 min. At the end of the experiments (after 120 min MCA occlusion) heads were frozen in situ with liquid nitrogen. Cooled brains were cut into 0.5 cm thick slices. From these slices twenty-micron sections passing through the territory of the MCA were prepared in a cryostat and used in the pictorial presentation of glucose and ATP. NADH-fluorescence was recorded from the tissue slice, immersed in liquid nitrogen. In addition, tissue samples were taken from regions of interest and used for quantitative determination of biochemical substrates. In all but two animals permanent MCA occlusion led to disturbances in the energy-producing metabolism, as indicated by reduction in glucose and ATP, and increase in lactate. The regions exhibiting bright NADH-fluorescence were much smaller than those in which ATP was absent. In 6 animals NADH-fluorescence was not increased but even decreased in areas with disturbed energy-producing metabolism. A close correlation was obtained after comparing cortical blood flow measured 15 min after MCA occlusion with the area of ATP-depletion at the end of the experiments. However, the size of ATP-depletion did not correlate with flow measured 60 or 120 min after MCA occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Pial arterial pressure in cats following middle cerebral artery occlusion. 1. Relationship to blood flow, regulation of blood flow and electrophysiological function.

In lightly anesthetized cats, the left middle cerebral artery was occluded using a transorbital approach. Pial arterial pressure was measured with a feedback-controlled micropressure recording system in the territory of the occluded artery, and compared with changes of cortical blood flow, cortical steady potential and cortical EEG activity. After middle cerebral artery occlusion pial artery pressure fell from 56.2 +/- 1.6 to 7.8 +/- 0.4 mm Hg; during the following two hours it again slowly rose to about 15 mm Hg. Cortical heat conductance, as a measure of blood flow, decreased from 15.1 +/- 0.2 to 11.9 +/- 0.2 X 10(-4) cal X cm-1 X sec-1 X degrees C-1, and remained at this level throughout the observation period. Cortical steady potential shifted by 9.1 +/- 0.7 mV towards negativity, and EEG amplitude was reduced by about 50%. Pial arterial pressure correlated with blood flow, cortical steady potential and EEG amplitude, but not with EEG frequency. Autoregulation and CO2 reactivity of blood flow were disturbed after middle cerebral artery occlusion. Calculation of extra- and intracortical vascular resistances revealed that this disturbance was entirely due to intracortical vasoparalysis whereas the collateral vessels supplying the ischemic territory continued to react to both pressure and CO2 changes. Maintained vascular reactivity of collateral vessels, therefore, is a decisive factor for the efficiency of therapeutic blood flow improvement after acute middle cerebral artery occlusion.

Effect of pentobarbital anesthesia and surgery on the control of arterial pressure and mesenteric resistance in cats: role of vasopressin and angiotensin.

We compared the effects of pentobarbital-induced anesthesia and major surgery (laparotomy) on the mesenteric resistance vessels and arterial pressure of cats. Intravenous infusion of sodium pentobarbital (30 mg/kg over 30--60 min) into conscious and unrestrained cats caused only a small increase in superior mesenteric arterial conductance and a small fall in femoral arterial pressure. In contrast to the effects of pentobarbital, major surgery caused marked mesenteric vasoconstrictor and pressor responses. Under these conditions, acute hypophysectomy and infusion of [Sar1, Ala8]angiotension II (saralasin) caused mesenteric conductance and arterial pressure to return towards presurgery control values. The results suggest that the high arterial pressure and constricted state of the mesenteric bed seen in acute experiments appears to be related to surgical stress rather than pentobarbital-induced anesthesia and that both the vasopressin system and the renin-angiotensin system appear to play important roles in the control of arterial pressure and the mesenteric resistance vessels under these conditions.

Effect of nonachlazine on the cardiac component of the baroreceptor reflex in unanesthetized cats

Nonachlazin in doses of 1 and 6 mg/kg provoked a rise in the arterial pressure of cats by 7--20 mm Hg. Administration of 1 mg nonaclazin into the IV ventricle induced a similar elevation of arterial pressure. Premedication with propranolol (1--3 mg/kg) did not prevent the pressor reaction. In half of the experiments, nonachlazin (6 mg/kg) produced an appearance of Meyer's waves and inhibition of the cardiac component of the barorecptor reflex that is not related to the potentiation of the sympathetic effects on the heart.

Dynamic pressures in the pial arterial microcirculation.

Dynamic pressures in the pial arterial microcirculation.

Action of a sympathomimetic drug and of theophylline ethylene diamine on the pulmonary circulation.

The action of two drugs, β-(2,5-diethoxyphenyl)-β-hydroxy-isopropylamine (BW 45/50) and theophylline ethylene diamine, on the pulmonary circulation of dogs and cats was tested. These experiments were made on intact animals, or animals with open chests, or on isolated perfused lungs. BW 45/50 reduced pulmonary arterial pressure in cats and dogs probably because of a fall in cardiac output; pulmonary vascular resistance was usually increased. Theophylline ethylene diamine caused a decrease in pulmonary vascular resistance; its value in pulmonary embolism is suggested.

The effect of intravenous infusion of blood serum and plasma from hypertensive and nephiritic patientsion arterial pressure

In short experiments it was shown that the effect of intravenous infusion of blood serum and plasma of hypertensive and nephritic patients upon the arterial pressure of cats and dogs is the same as the infusion of blood serum and plasma of healthy individuals.