. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. BIVALVE NERVES OXYGEN DEMAND Table I Oxygen consumption rates of bivalve cerebro-visceral connectives 349 Pulses Tellina Spisula Macrocallista Tagelus Geukensia per second Units ahernata solidissima nimbosa plebeius* demissa* 0 nmol O; g" â min"1 ± ± ± ± (ll)b (8) (2) (15) (7) 2 nmol 02 g~ 1 min"' ± ± ± ± (5) (7) (2) (5) (4) 2 nmol O; g~ pulse'' 2 nmol 02 g~ 1 pulse'' above resting 0.
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. BIVALVE NERVES OXYGEN DEMAND Table I Oxygen consumption rates of bivalve cerebro-visceral connectives 349 Pulses Tellina Spisula Macrocallista Tagelus Geukensia per second Units ahernata solidissima nimbosa plebeius* demissa* 0 nmol O; g" â min"1 ± ± ± ± (ll)b (8) (2) (15) (7) 2 nmol 02 g~ 1 min"' ± ± ± ± (5) (7) (2) (5) (4) 2 nmol O; g~ pulse'' 2 nmol 02 g~ 1 pulse'' above resting a Species without neurohemoglobin. b Numbers are given as average ± standard deviation (number of repetitions). much greater extent than the rates of connectives with neurohemoglobin (Fig. 1, Table I). During experiments with neurohemoglobin-containing connectives, mini- mum PO; of the air-equilibrated seawater drawn through the capillary rarely fell below 100 mmHg, a magnitude greater P02 than required to fully saturate the neurohemoglobin in situ (Doeller and Kraus, 1988). In addition, the active oxygen consumption rates remained the same when the neurohemoglobin oxygen binding ability was eliminated with 3-5 mmHg PCO ( < P < ). The resting and active oxygen consumption rates of connectives without neurohemoglobin were not affected by this partial pressure of carbon monoxide ( <P< ). The oxygen consumption rates of connectives with and without neurohemoglobin generally increased with increasing stimulus frequency (Fig. 2). Connectives with- out neurohemoglobin exhibited maximum oxygen con- sumption rates at a stimulus frequency of 2-3 pulses per second (Fig. 2). At higher stimulus rates, fewer axons may be conducting action potentials, as evidenced by a decrease in compound action potential amplitude, and this may lead to the observed decline in oxygen con- sumption rates. In contrast, connectives with neurohe-
Size: 1805px × 1384px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
