scholarly journals Why is there no carbonic anhydrase activity available to fish plasma?

1995 ◽  
Vol 198 (1) ◽  
pp. 31-38 ◽  
Author(s):  
J Lessard ◽  
A Val ◽  
S Aota ◽  
D Randall
Keyword(s):  
Carbonic Anhydrase ◽  
Blood Cell ◽  
Cell Volume ◽  
Red Blood Cell ◽  
Short Circuit ◽  
Hemoglobin Concentration ◽  
Carbonic Anhydrase Activity ◽  
Control Group ◽  
Acid Loading

Carbonic anhydrase (CA) is absent from the plasma of vertebrates. In vitro, CA in fish plasma will short-circuit the effect of catecholamines, which is to increase red blood cell (RBC) pH and volume, both of which enhance the affinity of hemoglobin for O2. CA was infused into trout for a period of 6 h and injected after 48 h, during which the animal was submitted to deep hypoxia (PO2=30­35 mmHg; 4.0­4.7 kPa). O2 content, lactate content, catecholamine levels, hematocrit, hemoglobin concentration and pHi were similar to those in the saline-infused control group. In contrast, cell volume was significantly higher and pHe, total CO2 content and organic phosphate levels were significantly lower than in the control group. The concentration of CA was not high enough completely to short-circuit the increase in pHi and red blood cell volume caused by catecholamines. The lower pHe in the CA-infused animals could enhance the activity of the Na+/H+ pump, which would keep the nucleotide triphosphate levels low. pH is a balance between acid loading at the muscle and acid excretion at the gills or the kidneys; we cannot distinguish between which of these resulted in a decrease of plasma pH. In conclusion, CA in plasma did not cause the expected reduction in blood oxygen content but did have a marked effect on plasma total CO2 content.

scholarly journals In Vitro Mean Red Blood Cell Volume Change Induced by Diode Pump Solid State Low-Level Laser of 405 nm

2016 ◽  
Vol 34 (5) ◽  
pp. 211-214 ◽  
Author(s):  
Mustafa S. Al Musawi ◽  
Mohamad Suhaimi Jafar ◽  
Bassam T. Al-Gailani ◽  
Naser Mahmoud Ahmed ◽  
Fatanah Mohamad Suhaimi ◽  
...  
Keyword(s):  
Solid State ◽  
Blood Cell ◽  
Cell Volume ◽  
Volume Change ◽  
Red Blood Cell ◽  
Diode Pump ◽  
Low Level ◽  
Low Level Laser ◽  
Level Laser

Blood Volume Changes during Three-Week Residence at High Altitude

1970 ◽  
Vol 16 (1) ◽  
pp. 7-14 ◽  
Author(s):  
L G Myhre ◽  
D B Dill ◽  
F G Hall ◽  
D K Brown
Keyword(s):  
Carbon Monoxide ◽  
Blood Cell ◽  
High Altitude ◽  
Cell Volume ◽  
Plasma Volume ◽  
Red Blood Cell ◽  
Hemoglobin Concentration ◽  
Red Cell ◽  
Volume Changes ◽  
Cell Volumes

Abstract Circulating red blood cell volumes were determined by the carbon monoxide method, and plasma volumes were calculated in four men 20, 29, 71, and 75 years old, and two women 29 years of age before, during, and after exposure to an altitude of 3800 m. In the four youngest subjects there were early increases in hemoglobin concentration during the first days at the stated altitude attributed to decreases in plasma volume. At the same time, hemoglobin concentration decreased and plasma volume increased in the oldest subject. Red cell volumes were slow to change, and it was concluded that 3 weeks or more of exposure to this altitude are required to affect significantly the red cell volume in man.

scholarly journals Red blood cell carbonic anhydrase mediates oxygen delivery via the Root effect in red drum

2020 ◽  
Vol 223 (22) ◽  
pp. jeb232991
Author(s):  
Angelina M. Dichiera ◽  
Andrew J. Esbaugh
Keyword(s):  
Carbonic Anhydrase ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Fold Increase ◽  
Red Drum ◽  
Sciaenops Ocellatus ◽  
Scaling Exponent ◽  
Root Effect ◽  
Tightly Coupled

ABSTRACTOxygen (O2) and carbon dioxide (CO2) transport are tightly coupled in many fishes as a result of the presence of Root effect hemoglobins (Hb), whereby reduced pH reduces O2 binding even at high O2 tensions. Red blood cell carbonic anhydrase (RBC CA) activity limits the rate of intracellular acidification, yet its role in O2 delivery has been downplayed. We developed an in vitro assay to manipulate RBC CA activity while measuring Hb-O2 offloading following a physiologically relevant CO2-induced acidification. RBC CA activity in red drum (Sciaenops ocellatus) was inhibited with ethoxzolamide by 53.7±0.5%, which prompted a significant reduction in O2 offloading rate by 54.3±5.4% (P=0.0206, two-tailed paired t-test; n=7). Conversely, a 2.03-fold increase in RBC CA activity prompted a 2.14-fold increase in O2 offloading rate (P<0.001, two-tailed paired t-test; n=8). This approximately 1:1 relationship between RBC CA activity and Hb-O2 offloading rate coincided with a similar allometric scaling exponent for RBC CA activity and maximum metabolic rate. Together, our data suggest that RBC CA is rate limiting for O2 delivery in red drum.

scholarly journals Regulation of blood volume in lowlanders exposed to high altitude

2017 ◽  
Vol 123 (4) ◽  
pp. 957-966 ◽  
Author(s):  
Christoph Siebenmann ◽  
Paul Robach ◽  
Carsten Lundby
Keyword(s):  
Blood Cell ◽  
High Altitude ◽  
Cell Volume ◽  
Blood Volume ◽  
Plasma Volume ◽  
Red Blood Cell ◽  
Hemoglobin Concentration ◽  
Circulating Blood Volume ◽  
Oxyhemoglobin Saturation ◽  
Physiological Relevance

Humans ascending to high altitude (HA) experience a reduction in arterial oxyhemoglobin saturation and, as a result, arterial O2content ([Formula: see text]). As HA exposure extends, this reduction in [Formula: see text] is counteracted by an increase in arterial hemoglobin concentration. Initially, hemoconcentration is exclusively related to a reduction in plasma volume (PV), whereas after several weeks a progressive expansion in total red blood cell volume (RCV) contributes, although often to a modest extent. Since the decrease in PV is more rapid and usually more pronounced than the expansion in RCV, at least during the first weeks of exposure, a reduction in circulating blood volume is common at HA. Although the regulation of hematological responses to HA has been investigated for decades, it remains incompletely understood. This is not only related to the large number of mechanisms that could be involved and the complexity of their interplay but also to the difficulty of conducting comprehensive experiments in the often secluded HA environment. In this review, we present our understanding of the kinetics, the mechanisms and the physiological relevance of the HA-induced reduction in PV and expansion in RCV.

Sign in / Sign up

Export Citation Format

Share Document