Melatonin deprival in young rats induces alterations in cerebral arteriolar wall similar to those observed during aging: atrophy and a decrease in distensibility. In this study, we examined the effects of melatonin treatment on cerebral arteriolar structure and distensibility and on the lower limit of cerebral blood flow autoregulation (LLCBF) in old rats. We measured cerebral blood flow (arbitrary unit, laser Doppler, open skull preparation) prior to and during stepwise hypotension (SH) in adult (12/13 months) and old (24/25 months) IcoWI and WAG/Rij male rats. Old rats were untreated or treated for 3 months with melatonin (0.39 (IcoWi) and 0.44 (Wag/Rij) mg kg-1 day-1, drinking water). Stress-strain relationships were determined using cross-sectional area (CSA, microm2, histometry) and values of arteriolar internal diameter (microm) obtained during a second SH following arteriolar deactivation (EDTA, 67 mmol l(-1)). Aging induced (a) atrophy of the arteriolar wall in IcoWI (616+/-20 vs 500+/-27 microm2, P<0.05) but not in WAG/Rij rats (328+/-25 vs 341+/-20 microm2), (b) a decrease in arteriolar wall distensibility and (c) an increase in the LLCBF in both strains (67+/-10 mmHg in 12-month-old vs 95+/-6 mmHg in 24-month-old IcoWi, P<0.05 and 53+/-2 mmHg in 13-month-old vs 67+/-6 mmHg in 25-month-old WAG/Rij). Melatonin treatment induced in IcoWI and WAG/Rij rats (a) hypertrophy of the arteriolar wall (643+/-34 and 435+/-25 microm2, respectively), (b) an increase in arteriolar wall distensibility and (c) a decrease in the LLCBF (64+/-6 and 45+/-4 mmHg, respectively). Melatonin treatment of old rats induced hypertrophy of the arteriolar wall, prevented the age-linked decrease in cerebral arteriolar distensibility and decreased the LLCBF. British Journal of Pharmacology (2004) 141, 399-406. doi:10.1038/sj.bjp.0705629

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1574212PMC
http://dx.doi.org/10.1038/sj.bjp.0705629DOI Listing

Publication Analysis

Top Keywords

cerebral arteriolar
8
arteriolar wall
8
cerebral blood
8
blood flow
8
cerebral
5
rats
5
arteriolar
5
impact treatment
4
melatonin
4
treatment melatonin
4

Similar Publications

The Optical Nature of Myopic Changes in Retinal Vessel Caliber.

Ophthalmol Sci

October 2024

Robert O Curle Ophthalmology Suite, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, UK.

Purpose: Dimensional measures of retinal features are subject to the optical influence of ocular magnification. We examined the impact of ocular magnification on the association between axial length (AL) and measurements of retinal vessel caliber in fundus photographs.

Design: Cross-sectional study.

View Article and Find Full Text PDF

Purpose: To describe the clinical findings in an 11-year-old male with a history of hemifacial microsomia presenting with ocular ischemic syndrome secondary to large cerebral aneurysms.

Observations: An 11-year-old male with a history of hemifacial microsomia presented to the Bascom Palmer Eye Institute Emergency Department complaining of nausea, diarrhea, headache, and decreased vision in the left eye. Visual acuity was light perception in the left eye and intraocular pressure was within normal limits.

View Article and Find Full Text PDF

Retinal blood vessel diameter changes with 60-day head-down bedrest are unaffected by antioxidant nutritional cocktail.

NPJ Microgravity

November 2024

Gravitational Physiology and Medicine Research Unit, Division of Physiology and Pathophysiology, Otto Loewi Research Center of Vascular Biology, Immunity and Inflammation, Medical University of Graz, Graz, Austria.

Article Synopsis
  • Long-term head-down bedrest (HDBR) simulates weightlessness and negatively impacts the retina and cerebrovascular regulation in healthy males.
  • Participants experienced a decrease in retinal arteriolar diameter by day 8 and an increase in venular diameter by day 16, along with higher blood pressure and lower cerebral blood flow velocity during HDBR.
  • An anti-inflammatory/antioxidant cocktail did not reverse these vascular changes, suggesting it was ineffective in restoring normal microcirculation and cerebral blood flow.
View Article and Find Full Text PDF

Unlocking the regenerative key: Targeting stem cell factors for bone renewal.

J Tissue Eng

October 2024

Department of Polymer Science and Engineering, Korea National University of Transportation, Chungju, Republic of Korea.

Stem cell factors (SCFs) are pivotal factors existing in both soluble and membrane-bound forms, expressed by endothelial cells (ECs) and fibroblasts throughout the body. These factors enhance cell growth, viability, and migration in multipotent cell lineages. The preferential expression of SCF by arteriolar ECs indicates that arterioles create a unique microenvironment tailored to hematopoietic stem cells (HSCs).

View Article and Find Full Text PDF

Background: Hypertensive pregnancies are associated with an increased risk of cardiovascular and neurological diseases in the offspring during later life. However, less is known about the potential impact on multi-organ phenotypes in offspring before disease symptoms occur. The objective of this systematic review was to determine the associations of fetal exposure to maternal hypertensive pregnancy with multi-organ phenotypes across developmental stages.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!