P2X1 receptors and the endothelium

First evidence of Tityus confluens Borelli, 1899 (Buthidae) venom altering purine metabolism in rat blood cells

Purinergic signaling pathways play crucial roles in regulating hemostatic and inflammatory responses, both of which are impacted by scorpion envenomation. Scorpion venoms are complex mixtures of various toxins, such as peptides, enzymes, and nucleotides. Previous research showed that the action of scorpion toxins on the purinergic system stems from their effects on purinergic receptors. Additionally, a study identified a putative ectonucleotidase in scorpion venom. This study aimed to investigate the ability of Tityus confluens venom (10, 50, and 100 µg/mL) to metabolize adenine nucleotides and its potential effects on purinergic enzyme activity in rat platelets and lymphocytes. The effects of T. confluens venom on E-NTPDase (ATP and ADP hydrolysis), E-5'-NT (AMP hydrolysis), and E-ADA (ADO hydrolysis) activities were analyzed. The results revealed that crude venom from T. confluens exhibited ATP hydrolysis activity at all tested concentrations. In lymphocytes, ADP hydrolysis was inhibited by 100 µg/mL crude venom, whereas ADO hydrolysis was increased by all venom concentrations. In platelets, ATP hydrolysis was inhibited by 50 and 100 µg/mL crude venom, whereas AMP and ADO hydrolysis were inhibited by all concentrations. When considered collectively, the data suggested an elevation in extracellular ATP levels and a reduction in extracellular ADO. These findings are in alignment with clinical manifestations of scorpion envenomation characterized by a pro-inflammatory milieu. Furthermore, this study demonstrated the intrinsic ATPase activity of T. confluens venom and its ability to modulate E-NTPDase, E-5'-NT, and E-ADA activities in rat blood cells.

Gene expression profiles of ion channels and receptors in mouse resistance arteries: Effects of cell type, vascular bed, and age

OBJECTIVE

Receptors and ion channels of smooth muscle cells (SMCs) and endothelial cells (ECs) are integral to the regulation of vessel diameter and tissue blood flow. Physiological roles of ion channels and receptors in skeletal muscle and mesenteric arteries have been identified; however, their gene expression profiles are undefined. We tested the hypothesis that expression profiles for ion channels and receptors governing vascular reactivity vary with cell type, vascular bed, and age.

METHODS

Mesenteric and superior epigastric arteries were dissected from Old (24-26 months) and Young (3-6 months) C57BL/6J mice. ECs and SMCs were collected for analysis with custom qRT-PCR arrays to determine expression profiles of 80 ion channel and receptor genes. Bioinformatics analyses were applied to gain insight into functional interactions.

RESULTS

We identified 68 differences in gene expression with respect to cell type, vessel type, and age. Heat maps illustrate differential expression, and distance matrices predict patterns of coexpression. Gene networks based upon protein-protein interaction datasets and KEGG pathways illustrate biological processes affected by specific differences in gene expression.

CONCLUSIONS

Differences in gene expression profiles are most pronounced between microvascular ECs and SMCs with subtle variations between vascular beds and age groups.