TY - JOUR
T1 - Cardiorespiratory Effects of Gap Junction Blockade in the Locus Coeruleus in Unanesthetized Adult Rats
AU - Patrone, Luis Gustavo Alexandre
AU - Bicego, Kenia Cardoso
AU - Hartzler, Lynn K.
AU - Putnam, Robert W.
AU - Gargaglioni, Luciane H.
PY - 2014/1/1
Y1 - 2014/1/1
N2 - The locus coeruleus (LC) plays an important role in central chemoreception. In young rats (P9 or younger), 85% of LC neurons increase firing rate in response to hypercapnia vs. only about 45% of neurons from rats P10 or older. Carbenoxolone (CARB – gap junction blocker) does not affect the % of LC neurons responding in young rats but it decreases the % responding by half in older animals. We evaluated the participation of gap junctions in the CO 2 ventilatory response in unanesthetized adult rats by bilaterally microinjecting CARB (300 μM, 1 mM or 3 mM/100 nL), glycyrrhizic acid (GZA, CARB analog, 3 mM) or vehicle (aCSF – artificial cerebrospinal fluid) into the LC of Wistar rats. Bilateral gap junction blockade in LC neurons did not affect resting ventilation; however, the increase in ventilation produced by hypercapnia (7% CO 2 ) was reduced by ∼25% after CARB 1 mM or 3 mM injection (1939.7 ± 104.8 mL kg −1 min −1 for the aCSF group and 1468.3 ± 122.2 mL kg −1 min −1 for 1 mM CARB, P < 0.05; 1939.7 ± 104.8 mL kg −1 min −1 for the aCSF group and 1540.9 ± 68.4 mL kg −1 min −1 for the 3 mM CARB group, P < 0.05) due largely to a decrease in respiratory frequency. GZA injection or CARB injection outside the LC (peri-LC) had no effect on ventilation under any conditions. The results suggest that gap junctions in the LC modulate the hypercapnic ventilatory response of adult rats.
AB - The locus coeruleus (LC) plays an important role in central chemoreception. In young rats (P9 or younger), 85% of LC neurons increase firing rate in response to hypercapnia vs. only about 45% of neurons from rats P10 or older. Carbenoxolone (CARB – gap junction blocker) does not affect the % of LC neurons responding in young rats but it decreases the % responding by half in older animals. We evaluated the participation of gap junctions in the CO 2 ventilatory response in unanesthetized adult rats by bilaterally microinjecting CARB (300 μM, 1 mM or 3 mM/100 nL), glycyrrhizic acid (GZA, CARB analog, 3 mM) or vehicle (aCSF – artificial cerebrospinal fluid) into the LC of Wistar rats. Bilateral gap junction blockade in LC neurons did not affect resting ventilation; however, the increase in ventilation produced by hypercapnia (7% CO 2 ) was reduced by ∼25% after CARB 1 mM or 3 mM injection (1939.7 ± 104.8 mL kg −1 min −1 for the aCSF group and 1468.3 ± 122.2 mL kg −1 min −1 for 1 mM CARB, P < 0.05; 1939.7 ± 104.8 mL kg −1 min −1 for the aCSF group and 1540.9 ± 68.4 mL kg −1 min −1 for the 3 mM CARB group, P < 0.05) due largely to a decrease in respiratory frequency. GZA injection or CARB injection outside the LC (peri-LC) had no effect on ventilation under any conditions. The results suggest that gap junctions in the LC modulate the hypercapnic ventilatory response of adult rats.
KW - Carbenoxolone
KW - Hypercapnia
KW - A6
KW - Ventilation
KW - Electrical Coupling
UR - https://corescholar.libraries.wright.edu/biology/179
U2 - 10.1016/j.resp.2013.09.001
DO - 10.1016/j.resp.2013.09.001
M3 - Article
C2 - 24035835
VL - 190
JO - Respiratory Physiology Neurobiology
JF - Respiratory Physiology Neurobiology
ER -