Control of breathing in African lungfish (Protopterus dolloi): a comparison of aquatic and cocooned (terrestrialized) animals.
African lungfish, Protopterus dolloi exhibited constant rates of O(2) consumption before (0.95+/-0.07 mmol kg(-1) h(-1)), during (1.21+/-0.32 mmol kg(-1) h(-1)) and after (1.14+/-0.14 mmol kg(-1) h(-1)) extended periods (1-2 months) of terrestrialization while cocooned. Although a breathing event in terrestrialized fish consisted of multiple bouts of inspiration and expiration in rapid succession, the mean frequency of pulmonary breathing events was unaltered in the terrestrialized fish (16.7+/-1.4 h(-1)versus 20.1+/-4.9 h(-1) in the aquatic and terrestrialized fish, respectively). Hypoxia (approximately 20 mmHg) increased the frequency of breathing events by 16 and 23 h(-1) in the aquatic and terrestrialized fish, respectively. Hyperoxia (approximately 550 mmHg) decreased breathing event frequency by 10 and 15 h(-1) in the aquatic and terrestrialized animals. Aquatic hypercapnia (approximately 37.5 mmHg) increased pulmonary breathing frequency (from 15.3+/-2.3 to 28.7+/-5.4 h(-1)) in free swimming lungfish, whereas aerial hypercapnia was without effect in aquatic or terrestrialized fish.
Perry
S F
SF
Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, Ont. K1N 6N5, Canada. sfperry@uottawa.ca
Euverman
R
R
Wang
T
T
Loong
A M
AM
Chew
S F
SF
Ip
Y K
YK
Gilmour
K M
KM
D000818:Animals; D001784:Blood Gas Analysis; D002395:Catecholamines / Q000097:blood; D004956:Estivation / Q000502:physiology*; D005399:Fishes / Q000502:physiology*; D006935:Hypercapnia / Q000503:physiopathology; D018496:Hyperoxia / Q000503:physiopathology; D000860:Hypoxia / Q000503:physiopathology; D008660:Metabolism / Q000502:physiology; D010101:Oxygen Consumption; D015656:Respiratory Mechanics / Q000502:physiology*; D013045:Species Specificity
D002395:Catecholamines