Role of adenosine in hypoxic ventilatory depression.
The role of adenosine in the ventilatory depression induced by hypoxia was studied in 82 spontaneously breathing urethan-anesthetized 4-day-old rabbit pups. Respiration was monitored with a pneumotachograph. The animals were exposed to hypoxia (6% O2 in N2) for 30 min or until the occurrence of terminal apnea. In all animals hypoxia produced an initial increase in ventilation followed by a decrease. In the control group 52% of the animals became apneic after 7 min of hypoxic exposure. By contrast, pretreatment with dipyridamole (10 or 20 mg/kg), an adenosine uptake blocker, significantly shortened the time needed to reach apnea. Thus at 7 min of hypoxia 93% of the animals that received dipyridamole became apneic. On the other hand, administration of adenosine antagonists 8-p-sulfophenyltheophylline (5 or 8 mg/kg) and aminophylline (10 or 25 mg/kg) significantly prolonged the time required to produce apnea. Only 20% of the animals that received these antagonists became apneic at 7 min of hypoxia. These results suggest that adenosine is potentially involved in the ventilatory depression produced by hypoxia in neonatal rabbit pups.
Runold
M
M
Department of Pharmacology, Karolinska Institutet, Stockholm, Sweden.
Lagercrantz
H
H
Prabhakar
N R
NR
Fredholm
B B
BB
D000241:Adenosine / Q000502:physiology*; D000628:Aminophylline / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure; D004176:Dipyridamole / Q000494:pharmacology; D010101:Oxygen Consumption; D011817:Rabbits; D012119:Respiration / Q000187:drug effects*; D012137:Respiratory System / Q000378:metabolism; D013997:Time Factors
D000628:Aminophylline; D004176:Dipyridamole; D000241:Adenosine