Our previous data indicated that various subtypes of connexin (Cx) were expressed in the juxtaglomerular apparatus. Experiments were performed to characterize the effects on renal autoregulation of specific mimetic peptides that inhibit these Cx subtypes in Wistar-Kyoto rats. Intrarenal infusion of (Cx37,43)GAP27 increased autoregulatory index of renal plasma flow (0.06 +/- 0.05 to 0.47 +/- 0.06, n = 6, P < 0.05) and glomerular filtration rate (GFR; 0.01 +/- 0.07 to 0.49 +/- 0.07, P < 0.05). The additional administration of 8-cyclopentyl- 1,3-dipropylxanthine (CPX) produced a further elevation of autoregulatory index of RPF (0.86 +/- 0.07, P < 0.05) and GFR (0.88 +/- 0.09, P < 0.05), compared with (Cx37,43)GAP27 alone. However, the addition of pyridoxal-phosphate-6-azophenyl-2,4-disulfonic acid (PPADS) to (Cx37,43)GAP27 did not. Combined treatment with CPX and PPADS markedly worsened autoregulatory index of RPF (0.04 +/- 0.10 to 0.81 +/- 0.06, n = 6 P < 0.01) and GFR (0.05 +/- 0.08 to 0.79 +/- 0.05, P < 0.01). (Cx40)GAP27 induced similar changes to (Cx37,43)GAP27. Renal autoregulation was preserved in the presence of (Cx43)GAP26. Our results indicate that the inhibition of gap junction impaired renal autoregulation. Furthermore, the present data provide evidence that both adenosine and purinergic receptors contribute to glomerular autoregulation. Finally, our findings suggest that gap junctions, at least in part, transduce purinergic signals mediating renal autoregulation.
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http://dx.doi.org/10.1152/ajpregu.00269.2007 | DOI Listing |
Clin Pharmacokinet
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Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa.
As people age, the efficiency of various regulatory processes that ensure proper communication between cells and organs tends to decline. This deterioration can lead to difficulties in maintaining homeostasis during physiological stress. This includes but is not limited to cognitive impairments, functional difficulties, and issues related to caregivers which contribute significantly to medication errors and non-adherence.
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December 2024
Departamento de Ciencias Básicas de la Salud, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Avda. de Atenas s/n, 28922 Alcorcón, Madrid, Spain.
Proc Natl Acad Sci U S A
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Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, AB T3E 6K6, Canada.
With over 14 million people living above 3,500 m, the study of acclimatization and adaptation to high altitude in human populations is of increasing importance, where exposure to high altitude (HA) imposes a blood oxygenation and acid-base challenge. A sustained and augmented hypoxic ventilatory response protects oxygenation through ventilatory acclimatization, but elicits hypocapnia and respiratory alkalosis. A subsequent renally mediated compensatory metabolic acidosis corrects pH toward baseline values, with a high degree of interindividual variability.
View Article and Find Full Text PDFAm J Physiol Endocrinol Metab
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Autonomic Physiology Laboratory, Faculty of Life Science and Human Technology, Nara Women's University, Kita-Uoya Nishimachi, Nara, 630-8506, Japan.
The current study aimed to propose a method to directly measure right cervical vagal nerve activity (cVNA) alongside renal sympathetic nerve activity (RSNA) in conscious rats. The right cervical vagus nerve was surgically exposed and fitted with a bipolar electrode to record cVNA. A microcatheter was used to administer levobupivacaine to selectively block afferent cVNA.
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Carol & Richard Yu Peritoneal Dialysis Research Centre, Department of Medicine & Therapeutics, Prince of Wales Hospital, Shatin, Hong Kong, China.
Background: Weight gain is common after starting peritoneal dialysis (PD). Several adiposity indices have been developed recently as potential indicators of visceral adiposity and lipid accumulation. We aim to investigate the prevalence and prognostic implications of the change in adiposity indices after 1 year of PD.
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