Sevoflurane Enhances Nitroglycerin Tolerance in Rat Aorta: Implications for the Desensitization of Soluble Guanylate Cyclase Possibly Through the Additive Generation of Superoxide Anions and/or Hydroxyl Radicals Within Vascular Smooth Muscle

Soluble Guanylate Cyclase α1 Gene Influences Egg-Laying Amount and Hatching Rate in Bombyx mori

Soluble guanylate cyclase (sGC) serves as a receptor of nitric oxide (NO) and is the core metalloenzyme in the NO signal transduction pathway. sGC plays a key role in the NO-cGMP signal transduction pathway and participates in various physiological processes, including cell differentiation, neuron transmission, and internal environment homeostasis. sGC consists of two subunits, α and β, each subunit containing multiple isoforms. In this study, we cloned and analyzed the sGC-α1 gene in the silkworm Bombyx mori (BmsGC-α1). The BmsGC-α1 gene was expressed highest at the pupal stages. The highest BmsGC-α1 mRNA expression was observed in the head of fifth instar larvae and in fat body during the wandering stage of B. mori. Furthermore, we observed that feeding fifth instar larvae with thyroid hormone and nitroglycerin induced the expression of the BmsGC-α1 gene. Injection of BmsGC-α1 siRNA into silkworms at the prepupal stage resulted in a significant decrease in BmsGC-α1 expression levels at 48 and 72 h postinjection. After silencing BmsGC-α1, both the egg-laying amount and hatching rate of silkworm eggs were significantly reduced compared to the control group. These results suggest that BmsGC-α1 plays an important role in regulating the reproductive system of silkworms. This finding enhances our understanding of the functional diversity of sGC in insects.

Effect of sevoflurane pretreatment in relieving liver ischemia/reperfusion-induced pulmonary and hepatic injury

Purpose

To investigate the effect of sevoflurane preconditioning on ischemia/reperfusion (I/R)-induced pulmonary/hepatic injury

Methods

Fifty-one Wistar rats were randomly grouped into sham, I/R, and sevoflurane groups. After reperfusion, the structural change of the lung was measured by Smith score, the wet and dry weights (W/D) were determined, malondialdehyde (MDA) myeloperoxidase (MPO) content was determined colorimetrically and by fluorescence, respectively, and matrix metalloprotein-9 (MMP-9) mRNA was quantified by RT-PCR. Biopsy and morphological analyses were performed on liver tissue, activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were determined, and tumor necrosis factor-alpha (TNF-α) level was determined.

Results

The sham group showed no changes in tissue structure. Structural lesions in the sevoflurane and I/R groups were mild and severe, respectively. Smith score, W/D, MDA, MPO, and MMP mRNA showed the same trend, and were increased in the I/R group and recovered in the sevoflurane group, compared with the sham group (both P<0.05). AST and ALT were significantly increased compared to the sham group (AST: 655±52.06 vs . 29±9.30 U/L; ALT: 693±75.56 vs . 37±6.71 U/L; P<0.05). In the sevoflurane group, AST and ALT levels were significantly decreased (464±47.71 and 516±78.84 U/L; P<0.001). TNF-α presented similar results.

Conclusion

The protection of lung and liver by sevoflurane may be mediated by inhibited leukocyte recruitment and MMP-9 secretion.

Effects of Sevoflurane on Hemodynamics and Inducible Nitric Oxide Synthase/Soluble Guanylate Cyclase Signaling Pathway in a Rat Model of Pulmonary Arterial Hypertension

BACKGROUND

The effects of sevoflurane on right ventricular (RV) function are incompletely understood. In a rat model of experimentally induced pulmonary arterial hypertension (PAH), we studied effects of sevoflurane on RV function and the expression of inducible nitric oxide synthase/soluble guanylate cyclase (iNOS/sGC) signaling pathway. We hypothesized that sevoflurane would improve RV function in rats with PAH via a iNOS/sGC pathway.

METHODS

To induce PAH, Sprague-Dawley rats were randomly assigned to treatment with monocrotaline or normal saline. Four weeks later, rats were then randomly assigned to either control or sevoflurane inhalation. After rats were anesthetized and instrumented with a pulmonary artery or RV conductance catheter, they were treated with inhaled sevoflurane at 3 doses for 90 minutes each. Hemodynamic changes and expression of iNOS and sGC were recorded.

RESULTS

Sevoflurane inhalation depressed RV function in both normal and PAH rats. However, RV dP/dtmax fell to a lesser degree in rats with PAH than normal rats. Sevoflurane inhalation increased iNOS expression, but decreased sGC expression.

CONCLUSIONS

Sevoflurane depressed RV contractility to a lesser degree in PAH than in normal rats. Sevoflurane also upregulated iNOS expression and downregulated sGC expression in PAH, but not control rats. This observation may explain the differential effects of sevoflurane on RV function in rats with and without PAH.