English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Hypocarbia results in an increase in brain adenosine concentrations, presumably because of brain hypoxia associated with hypocarbic vasoconstriction. It was hypothesized that adenosine limits the degree of hypocarbic vasoconstriction. To test this hypothesis, the effects of dipyridamole and theophylline on CO 2  reactivity during hypocarbia were investigated in anesthetized rats. Dipyridamole should reduce the vasoconstriction by potentiating adenosine action, whereas theophylline should increase the vasoconstriction by blocking adenosine receptors. Cortical pial arterioles of mechanically ventilated and anesthetized rats were displayed on a video monitor system through a closed cranial window. Arterial blood pressure and oxygen tension were stable. CO 2  reactivity, formulated as 100 x [Δ diameter (μm)/resting diameter (μm)]/Δ P a CO 2  (mmHg), in the hypocarbic phase was calculated before and after topical superfusion of dipyridamole (10 −6  M; n = 7) and theophylline (5 × 10 −5  M; n = 6). CO 2  reactivity was significantly decreased after superfusion of dipyridamole (0.57 ± 0.08; mean ± SEM) as compared with mock cerebrospinal fluid (CSF) (0.97 ± 0.17, p &lt; 0.05, n = 7). On the other hand, CO 2  reactivity after superfusion of theophylline was increased (1.63 ± 0.28) as compared with mock CSF (1.00 ± 0.20, p &lt; 0.05, n = 6), indicating that adenosine is involved in hypocarbic vasoconstriction.

The Effects of Dipyridamole and Theophylline on Rat Pial Vessels during Hypocarbia