Characterization of Rat Cardiovascular System by Anacrotic/Dicrotic Notches in the Condition of Increase/Decrease of NO Bioavailability

Use of a rat model to characterize 35 arterial pulse wave parameters in a comparative study of isoflurane and Zoletil/xylazine anesthesia and the effect of Acanthopanax senticosus extract

BACKGROUND

Information obtained from arterial pulse waveforms (APW) can be useful for characterizing the cardiovascular system. To achieve this, it is necessary to know the detailed characteristics of APWs in different states of an organism, which would allow APW parameters (APW-Ps) to be assigned to particular (patho)physiological conditions. Therefore, our work aimed to characterize 35 APW-Ps in rats under the influence of isoflurane (ISO) and Zoletil/xylazine (ZO/XY) anesthesia and to study the effect of root extract from Acanthopanax senticosus (ASRE) in these anesthetic conditions.

METHODS

The right jugular vein of anesthetized rats was cannulated for the administration of ASRE and the left carotid artery for the detection of APWs from which 35 APW-Ps were evaluated.

RESULTS

We obtained data on 35 APW-Ps, which significantly depended on the anesthesia, and thus, they characterized the cardiovascular system under these two conditions. ASRE transiently modulated all 35 APW-Ps, including a transient decrease in systolic and diastolic blood pressure (BP) and heart rate or increases in pulse BP, dP/dtmax , and systolic and diastolic areas. Whereas the transient effects of ASRE were similar, the extract had prolonged disturbing effects on the cardiovascular system in rats under ZO/XY but not under ISO anesthesia. This negative effect can result from the disturbance caused by ZO/XY anesthesia on the cardiovascular system.

CONCLUSIONS

We characterized 35 APW-Ps of rats under ISO and ZO/XY anesthesia and found that ASRE contains compounds that can modulate the properties of the cardiovascular system, which significantly depended on the status of the cardiovascular system. This should be considered when using ASRE as a nutritional supplement by individuals with cardiovascular problems.

The Phthalic Selenoanhydride Decreases Rat Blood Pressure and Tension of Isolated Mesenteric, Femoral and Renal Arteries

Phthalic selenoanhydride (R-Se) solved in physiological buffer releases various reactive selenium species including H₂Se. It is a potential compound for Se supplementation which exerts several biological effects, but its effect on the cardiovascular system is still unknown. Therefore, herein we aimed to study how R-Se affects rat hemodynamic parameters and vasoactive properties in isolated arteries. The right jugular vein of anesthetized Wistar male rats was cannulated for IV administration of R-Se. The arterial pulse waveform (APW) was detected by cannulation of the left carotid artery, enabling the evaluation of 35 parameters. R-Se (1-2 µmol kg^-1), but not phthalic anhydride or phthalic thioanhydride, transiently modulated most of the APW parameters including a decrease in systolic and diastolic blood pressure, heart rate, dP/dt_max relative level, or anacrotic/dicrotic notches, whereas systolic area, dP/dt_min delay, dP/dt_d delay, anacrotic notch relative level or its delay increased. R-Se (~10-100 µmol L^-1) significantly decreased the tension of precontracted mesenteric, femoral, and renal arteries, whereas it showed a moderate vasorelaxation effect on thoracic aorta isolated from normotensive Wistar rats. The results imply that R-Se acts on vascular smooth muscle cells, which might underlie the effects of R-Se on the rat hemodynamic parameters.

Photosensitized co-generation of nitric oxide and singlet oxygen Enhanced toxicity against ovarian cancer cells

Near micromolar concentrations of nitric oxide (NO) induce tumor cells death. However, an appropriate NO load has to be delivered selectively to the tumor site in order to avoid NO loss and secondary NO-induced effects. The encapsulation of millimolar concentrations of a NO source and an appropriate trigger of NO release within phospatidylcholine-based liposomes should provide an efficient tool for the selective release of the needed NO payload. In this work we report the photosensitized generation of singlet oxygen and NO from folate-targeted PEGylated liposomes, containing AlPcS4 as the sensitizer and S-nitrosoglutathione (GSNO), in millimolar amounts, as the NO source. Amounts of singlet oxygen detected outside the liposome when using PEGylated liposomes are near 200 % larger when GSNO is present inside the liposomes as compared to its absence. These liposomes, conjugated to folate, were found to enhance the photosensitized cytotoxicity to A2780CP20 ovarian cancer cells as compared to liposomes containing the sensitizer but no GSNO (30 % as compared to 70 % cell viability) under the conditions of this work. Fluorescense of AlPcS4 was observed inside cells incubated with folate-conjugated liposomes but not with liposomes without folate. The photosensitized activity enhancement by GSNO increased when light fluence or liposome concentration were increased. The majority of ovarian cancer patients are initially diagnosed with disseminated intra-abdominal disease (stages III-IV) and have a 5-year survival of less than 20%. This work suggests a novel ovarian cancer nodules treatment via the use of tumor-targeted liposome nanoparticles with the capability of generating simultaneously reactive oxygen and nitrogen species upon illumination with near-infrared light.

Cardiovascular "Patterns" of H2S and SSNO--Mix Evaluated from 35 Rat Hemodynamic Parameters

This work is based on the hypothesis that it is possible to characterize the cardiovascular system just from the detailed shape of the arterial pulse waveform (APW). Since H₂S, NO donor S-nitrosoglutathione (GSNO) and their H₂S/GSNO products (SSNO⁻-mix) have numerous biological actions, we aimed to compare their effects on APW and to find characteristic “patterns” of their actions. The right jugular vein of anesthetized rats was cannulated for i.v. administration of the compounds. The left carotid artery was cannulated to detect APW. From APW, 35 hemodynamic parameters (HPs) were evaluated. H₂S transiently influenced all 35 HPs and from their cross-relationships to systolic blood pressure “patterns” and direct/indirect signaling pathways of the H₂S effect were proposed. The observed “patterns” were mostly different from the published ones for GSNO. Effect of SSNO⁻-mix (≤32 nmol kg⁻¹) on blood pressure in the presence or absence of a nitric oxide synthase inhibitor (L-NAME) was minor in comparison to GSNO, suggesting that the formation of SSNO⁻-mix in blood diminished the hemodynamic effect of NO. The observed time-dependent changes of 35 HPs, their cross-relationships and non-hysteresis/hysteresis profiles may serve as “patterns” for the conditions of a transient decrease/increase of blood pressure caused by H₂S.