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1.
M. -T. Linossier D. Dormois R. Fouquet A. Geyssant C. Denis 《European journal of applied physiology and occupational physiology》1996,74(5):420-427
A group of 15 untrained male subjects pedalled on a friction-loaded cycle ergometer as fast as possible for 5–7 s to reach
the maximal velocity (V{immax}) against different braking forces (F
B). Power was averaged during a complete crank rotation by adding the power dissipated againstF
B to the power necessary to accelerate the flywheel. For each sprint, determinations were made of peak power output (
) power output attained atV
max (
) calculated as the product ofV
max andF
B and the work performed to reachV
max expressed in mean power output (
). The relationships between these parameters andF
B were examined. A biopsy taken from the vastus lateralis muscle and tomodensitometric radiographs of both thighs were taken
at rest to identify muscle metabolic and morphometric properties. The
value was similar for allF
B. Therefore, the average of values was defined as corrected maximal power (
). This value was 11 higher than the maximal power output uncorrected for the acceleration. Whereas the
determination did not require high loads, the highest
value (
) was produced when loading was heavy, as evidenced by the
-F
B parabolic relationship. For each subject, the braking force (
) giving
was defined as optimal. The
, equal to 0.844 (SD 0.108) N · kg−1 bodymass, was related to thigh muscle area (r = 0.78,P < 0.05). The maximal velocity (
) reached against this force seemed to be related more to intrinsic fibre properties (% fast twitch b fibre area and adenylate
kinase activity). Thus, from the
determination, it is suggested that it should be possible to predict the conditions for optimal exercise on a cycle ergometer. 相似文献
2.
Absorption of gas from alveoli is examined in a simplified model of the respiratory system during a stylized single breath consisting of constant inspiratory flow, constant expiratory flow, and breathholding. The equations describing gas behavior are general since they are based upon conservation of mass. The equations simplify considerably when gases that are not soluble in pulmonary tissue and/or blood are utilized. In a three-compartment model, diffusing capacity of the lung for carbon monoxide (D
CO
) will be underestimated except when both uneven distribution of lung volume andD
CO
are present; under most circumstances, the standard clinical 10-s method [9] is at least as accurate as any other. When pulmonary capillary blood flow
is calculated by the one point method [2] in a one-compartment lung, it is underestimated; in the three-compartment model, it is underestimated except when both uneven distribution of
. and lung volume are present. The multiple single breath method [2] accurately measuresD
CO
and
. Measurement of pulmonary tissue volume is improved by correcting the value of the intercept of acetylene absorption to the time when carbon monoxide apparently began rather than utilizing the beginning of inspiration.Nomenclature
D
CO
diffusing capacity of the lung for CO (ml CO, STPD/min/mm Hg)
-
pulmonary capillary blood flow rate (L/min)
-
V
t
pulmonary tissue volume (L)
-
V
A
alveolar compartment volume (L)
-
V
Ao
alveolar compartment volume at conclusion of inspiratory flow (L)
-
inspiratory flow rate (L/sec)
-
expiratory flow rate (L/sec)
-
Bunsen coefficient of pulmonary tissue for test gas (ml test gas/ml tissue/atm)
-
Bunsen coefficient of pulmonary tissue for test gas (ml test gas/ml blood/atm)
-
F
A
fractional pressure of test gas in the alveolar compartment (atm) 相似文献
3.
Hugo M. Martinez 《Bulletin of mathematical biology》1966,28(3):411-416
IfN(t) is the expected number of cells in a culture at timet,
the corresponding time derivative, andf(t−τ)dt the probability that a cell of aget−τ at timet will divide in the succeeding time intervaldt, then according to Hirsch and Engelberg (this issue) there obtains the integral equation
for describing the dynamics of the cell population. It is the purpose of this note to give two alternative derivations of
this equation, one based on the age density equation of Von Foerster, and the other based on a generalized form of the Harris-Bellman
equation describing the first moment of an age dependent, branching process. In addition, a probability model is posed from
which the Von Foerster equation and, hence, the Hirsch-Engelberg equation readily follows. 相似文献
4.
Summary The complete sequence of the 5S rRNA from the bioluminescent bacterium,Beneckea harveyi has been determined to be p U G C U U G G C G
C C A U A G C G A
U U-G G A C C C A
C U G A (U) C U U C
A U U C C-G A A C
C A G A A G U G A
A C G A A U U A-G
G C C G A U G G U
G U G U G G G G C
U-C C C C A U G U
A G A G U A G G A
A U C G-C C A G G
U (U)OH.Two sites of sensitivity to ribonuclease T2 cleavage were identified; at A41 and either A54 or A55. Comparison with existing sequence information fromEscherichia coli andPhotobacterium phosphoreum clarifies the amount of diversity among the bioluminescent bacteria and provides further insight into their phylogenetic position. Sequence heterogeneities were encountered and the importance of these in interpreting 5S rRNA data is discussed. 相似文献
5.
Jack P. Hayes 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1989,159(4):453-459
Summary I compared the maximal aerobic metabolic rates (
), field metabolic rates (FMR), aerobic reserves (
-FMR), and basal metabolic rates (BMR) of wild and recently captured deer mice from low (440 m) and high (3800 m) altitudes. To separate the effects of the thermal environment from other altitudinal effects, I examined mice from different altitudes, but similar thermal environments (i.e., summer mice from high altitude and winter mice from low altitude). When the thermal environment was similar,
, FMR, and aerobic reserve of low and high altitude mice did not differ, but BMR was significantly higher at high altitude. Thus, in the absence of thermal differences, altitude had only minor effects on the aerobic metabolism of wild or recently captured deer mice.At low altitude, there was significant seasonal variation in
, FMR, and aerobic reserve, but not BMR. BMR was correlated with
, but not with FMR. The significant positive correlation of BMR with
indicates a cost of high
, because higher BMR increases food requirements and energy use during periods of thermoneutral conditions.Abbreviations
BMR
basal metabolic rate
-
FMR
field metabolic rate
-
partial pressure of oxygen
-
T
a
ambient temperature
-
T
b
body temperature
-
T
e
operative temperature
-
maximal aerobic metabolic rate 相似文献
6.
Lawrence A. Baker Dr. Wesley W. Weathers Fred N. White 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1972,80(3):312-323
Summary The influence of local temperature changes within the posterior portion of the body on dorsal aorta blood flow (
), femoral arterial pressure (P
a
), peripheral resistance (R), skin blood flow (
) and skeletal muscle blood flow (
) was examined in unanesthetized lizards (Iguana iguana andTubinambis nigropunctatus). In response to local heating of the hind legs and tail
and
increased,P
a
was generally unchanged,R decreased and
decreased or was unchanged (Fig. 2). It is suggested that the acquisition of heat may be favored by diverting the increase in
away from the muscle to the warmer skin. In response to cooling
and
decreased,P
a
was generally unchanged, R increased and
increased or was unchanged. Hence, during cooling the retention of heat may be favored by diverting blood away from the skin to the deeper muscle. The muscle-skin shunt is under sympathetic control since following blockade with phenoxybenzamine HCL (Dibenzyline) muscle blood flow changes in response to temperature were qualitatively similar to those of skin (Fig. 4). These changes in peripheral circulatory patterns are independent of changes in heart rate or deep body temperature.Baker and Weathers were predoctoral and postdoctoral trainees, respectively, under USPHS Grant HE-05696. This study was also supported by NSF Grant GB-8523 and Los Angeles County Heart Association Grant 437IG. 相似文献
7.
Summary A set of three-dimensional triple-resonance experiments is described which provide
,
,
and
coupling constants. The pulse sequences generate E.COSY-like multiplet patterns and comprise a magnetization transfer from
the amide proton to the α-proton or vice versa via the directly bound heteronuclei. For residues with the 1Hα spin resonating close to the H2O signal, a modified HNCA experiment can be employed to measure the vicinal 1HN,1Hα couplings. Ambiguities associated with the conversion of
values into ϕ-angle constraints for protein structure determination can be resolved with the knowledge of the heteronuclear
3J-couplings. In favourable cases, stereospecific assignments of glycine α-protons can be obtained by employing the experiments
described here in combination with NOE data. The methods are applied to flavodoxin from Desulfovibrio vulgaris. 相似文献
8.
Veronique Billat Jean C. Renoux Jacques Pinoteau Bernard Petit Jean P. Koralsztein 《European journal of applied physiology and occupational physiology》1994,69(3):271-273
The aim of this study was to measure running times to exhaustion (Tlim) on a treadmill at 100% of the minimum velocity which elicits
max
max in 38 elite male long - distance runners
max = 71.4 ± 5.5 ml.kg–1.min–1 and
max = 21.8 ± 1.2 km.h–1). The lactate threshold (LT) was defined as a starting point of accelerated lactate accumulation around 4 mM and was expressed in
max. Tlim value was negatively correlated with
max (r = -0.362, p< 0.05) and
max (r = –0.347, p< 0.05) but positively with LT (%v
max) (r = 0.378, p < 0.05). These data demonstrate that running time to exhaustion at
max in a homogeneous group of elite male long-distance runners was inversely related to
max and experimentally illustrates the model of Monod and Scherrer regarding the time limit-velocity relationship adapted from local exercise for running by Hughson et al. (1984) . 相似文献
9.
Robert Rosen 《Bulletin of mathematical biology》1963,25(2):231-241
It has been shown in earlier work that one approach to what Rashevsky has called “abstract biology” is through the study of
the class of (
)-systems that can be formed in an arbitrary subcategory of the category of sets. The concept of the (
)-system, however, depends on the availability of mappings that contain other mappings in their range. It is shown that, by
introducing an appropriate measure for this property, the problem of characterizing those categories suitable for a rich theory
of (
)-systems reduces to a problem familiar from the general theory of graphs. Some new results in these directions are obtained,
and it is then shown that any category with mappings that possess properties we might expect to hold in the physical world
will also admit a rich theory of (
)-systems. In particular, it is shown that a sufficiently large family of mappings drawn at random from such a category will
with overwhelming probability contain an (
)-system.
This research was supported by the United States Air Force through the Air Force Office of Scientific Research of the Air
Research and Development Command, under Grant No. AF-AFOSR-9-63. 相似文献
10.
Viktor Reinhardt 《Primates; journal of primatology》1987,28(1):123-125
The justification for the “generalization that primate males are more aggressive than females” (Fedigan & Baxter, 1984) was tested in a troop of 24 captive rhesus monkeys. Males (N=9) were more dominant than females (N=15), i.e., they had more subordinate partners (
m=17.0 vs.
f=6.6;p<0.01); hence, their aggression rate was higher (
m=77.6 vs.
m=38.1;p<0.05). However, adjusting the rate of aggression according to the number of subordinate targets revealed no gender difference
and males directed numbers of aggressive acts against individual subordinate partners that were not higher than those of females
(
m=4.4 vs.
f=5.4;p>0.1). It was concluded that aggressiveness is an individual attribute that is (1) independent of dominance status, and (2)
independent of sex. 相似文献
11.
W. Selvamurthy U. S. Ray K. S. Hegde R. P. Sharma 《International journal of biometeorology》1988,32(3):188-193
A study was conducted on 30 healthy soldiers (age: 40–46 years) to assess the effect of selected yogic exercises (asanas) on some physiological responses to cold exposure. They were randomly divided into two groups of 15 each. One group performed regular physical exercises of physical training (PT), while the other group practised yogic exercises. At the end of 6 months of training, both the groups were exposed together to cold stress at 10°C for 2 h, and the following parameters were periodically monitored during cold exposure: heart rate (fH), blood pressure (BP), cardiac output
, oral temperature (Tor), skin temperature (T
sk), respiratory rate (fR), minute ventilation
, oxygen consumption
, and shivering response by integrated electromyogram (EMG). There were progressive increases inBP, fR,
,
, and
and decreases infH,T
or andT
sk during cold exposure in both the groups. However, the decrease inT
or and the increases in
and
were relatively lower (P<0.01) in the yoga group as compared to the PT group. The shivering response appeared much earlier and was more intense in the PT group. These findings suggest that practice of yoga exercises may improve cold tolerance. 相似文献
12.
Summary
D. melanogaster males of
bb/O genetic constitution undergoing rDNA magnification were mated singly to XXbb
+/O females, yielding
bb/O male progeny, and to XNO-w sn bb
+ fameles, yielding
bb/XNO- females. The male and female offspring were scored for the bb
+ phenotype.Results show that there is a higher percentage of bb
+ flies in the
bb/O male progeny than in
bb/XNO- females progeny, in single crosses as well as in the combined data. rRNA/DNA hybridization experiments agree with this observation, by showing that the rDNA content in the progeny of premagnified flies was higher in the sons than in the daughters.These data indicate that the increase of ribosomal RNA genes is not due to a stable event such as an unequal mitotic sister exchange, whereas they do not contrast with the extracopy model. 相似文献
13.
D. L. Evans R. J. Rose 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1988,157(6):791-799
Summary Six Standardbred horses were used to evaluate the time course of pulmonary gas exchange, ventilation, heart rate (HR) and acid base balance during different intensities of constant-load treadmill exercise. Horses were exercised at approximately 50%, 75% and 100% maximum oxygen uptake (
max) for 5 min and measurements taken every 30 s throughout exercise. At all work rates, the minute ventilation, respiratory frequency and tidal volume reached steady state values by 60 s of exercise. At 100%
max, the oxygen consumption (
) increased to mean values of approximately 130 ml/kg·min, which represents a 40-fold increase above resting
. At the low and moderate work rates,
showed no significant change from 30 s to 300 s of exercise. At the high work rate, the mean
at 30 s was 80% of the value at 300 s. The HR showed no significant change over time at the moderate work rate but differing responses at the low and high work rates. At the low work rate, the mean HR decreased from 188 beats/min at 30 s to 172 beats/min at 300 s exercise, whereas at the high work rate the mean HR increased from 204 beats/min at 30 s to 221 beats/min at 300 s exercise. No changes in acid base status occurred during exercise at the low work rate. At the moderate work rate, a mild metabolic acidosis occurred which was nonprogressive with time, whereas the high work rate resulted in a progressive metabolic acidosis with a base deficit of 16 mmol/l by 300 s exercise. It is concluded that the kinetics of gas exchange during exercise are more rapid in the horse than in man, despite the relatively greater change in
in the horse when going from rest to high intensity exercise.Symbols and abbreviations E
minute ventilation
-
V
T
tidal volume
-
oxygen uptake
-
carbon dioxide output
-
oxygen pulse
-
ventilatory equivalent for oxygen
-
ventilatory equivalent for carbon dioxide
- R
respiratory exchange ratio
- HR
heart rate
- SBC
standard bicarbonate
- STPD
standard temperature and pressure dry
- BTPS
body temperature and pressure saturated
-
arterial oxygen content
-
arteriovenous oxygen content difference
- Rf
respiratory frequency 相似文献
14.
Didier G. Arqués Jean-Paul Fallot Christian J. Michel 《Bulletin of mathematical biology》1998,60(1):163-194
The self-complementary subset
∪{AAA,TTT} with
= {AAC, AAT, ACC, ATC, ATT, CAG, CTC, CTG, GAA, GAC, GAG, GAT, GCC, GGC, GGT, GTA, GTC, GTT, TAC, TTC} of 22 trinucleotides
has a preferential occurrence in the frame 0 (reading frame established by the ATG start trinucleotide) of protein (coding)
genes of both prokaryotes and eukaryotes. The subsets
∪{CCC} and
∪{GGG} of 21 trinucleotides have a preferential occurrence in the shifted frames 1 and 2 respectively (frame 0 shifted by
one and two nucleotides respectively in the 5′-3′ direction).
and
are complementary to each other. The subset
contains the subset
which has the rarity property (6 × 10−8) to be a complementary maximal circular code with two permutated maximal circular codes
and
in the frames 1 and 2 respectively.
is called a C3 code.
A quantitative study of these three subsets
in the three frames 0, 1, 2 of protein genes, and the 5′ and 3′ regions of eukaryotes, shows that their occurrence frequencies
are constant functions of the trinucleotide positions in the sequences. The frequencies of
in the frame 0 of protein genes are 49, 28.5 and 22.5% respectively. In contrast, the frequencies of
in the 5′ and 3′ regions of eukaryotes, are independent of the frame. Indeed, the frequency of
in the three frames of 5′ (respectively 3′) regions is equal to 35.5% (respectively 38%) and is greater than the frequencies
and
, both equal to 32.25% (respectively 31%) in the three frames.
Several frequency asymmetries unexpectedly observed (e.g. the frequency difference between
and
in the frame 0), are related to a new property of the subset
involving substitutions. An evolutionary analytical model at three parameters (p, q, t) based on an independent mixing of the 22 codons (trinucleotides in frame 0) of
with equiprobability (1/22) followed by t ≈ 4 substitutions per codon according to the proportions p ≈ 0.1; q ≈ 0.1 and r = 1 − p − q ≈ 0.8 in the three codon sites respectively, retrieves the frequencies of
observed in the three frames of protein genes and explains these asymmetries. Furthermore, the same model (0.1, 0.1, t) after t ≈ 22 substitutions per codon, retrieves the statistical properties observed in the three frames of the 5′ and 3′ regions.
The complex behaviour of these analytical curves is totally unexpected and a priori difficult to imagine. 相似文献
15.
B. Culik A. J. Woakes D. Adelung R. P. Wilson N. R. Coria H. J. Spairani 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1990,160(1):61-70
Summary The energy requirements of Adélie penguin (Pygoscelis adeliae) chicks were analysed with respect to body mass (W, 0.145–3.35 kg, n=36) and various forms of activity (lying, standing, minor activity, locomotion, walking on a treadmill). Direct respirometry was used to measure O2 consumption (
) and CO2 production. Heart rate (HR, bpm) was recorded from the ECG obtained by both externally attached electrodes and implantable HR-transmitters. The parameters measured were not affected by hand-rearing of the chicks or by implanting transmitters. HR measured in the laboratory and in the field were comparable. Oxygen uptake ranged from
in lying chicks to
at maximal activity, RQ=0.76. Metabolic rate in small wild chicks (0.14–0.38 kg) was not affected by time of day, nor was their feeding frequency in the colony (Dec 20–21). Regressions of HR on
were highly significant (p< 0.0001) in transmitter implanted chicks (n=4), and two relationships are proposed for the pooled data, one for minor activities (
), and one for walking (
). Oxygen consumption, mass of the chick (2–3 kg), and duration of walking (T, s) were related as
, whereas mass-specific O2 consumption was related to walking speed (S, m·s-1) as
.Abbreviations
bpm
beats per minute
-
D
distance walked (m)
-
ECG
electrocardiogram
-
HR
heart rate (bpm)
-
ns
number of steps
-
RQ
respiratory quotient
-
S
walking speed (m·s-1)
-
T
time walked (s)
-
W
body mass (kg) 相似文献
16.
Daniel T. Clemens 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1988,158(1):57-66
Summary Rosy finches (Leucosticte arctoa) breed at altitudes above 3500 m in eastern California. House finches (Carpodacus mexicanus) belong to the same subfamily (Carduelinae), but breed at much lower elevations. Oxygen consumption (
) and ventilatory parameters of these two species were measured over a wide range of ambient temperatures (T
a) at low altitude (LA; 150 m) and at high altitude (HA; 3800 m).Minimal nighttime
's of rosy finches and house finches at LA (T
a=30°C) were close to allometrically predicted values for passerine birds. At both altitudes,
increased linearly with decreasingT
a betweenT
a=20 and –10°C. Resting
's were slightly higher at HA than at LA on average.In both species, minute volume (
) was inversely related toT
a.T
a-correlated increases in
resulted from significant increases in both ventilatory frequency (f) and tidal volume (V
T) at both altitudes. Oxygen extraction efficiency (
) was independent ofT
a in rosy finches at LA, but declined significantly with decreasingT
a in rosy finches at HA and in house finches at both altitudes.At a givenT
a, both species had significantly greater
(BTPS) at HA than at LA. Altitude-correlated increases in
resulted primarly from increases inf with little change inV
T.
was significantly greater at HA than at LA in both species.In spite of the difference in altitudinal distributions of rosy finches and house finches, there were few conspicuous interspecific differences in metabolic or ventilatory adaptation to altitude or lowT
a over the range of conditions examined.Symbols and abbreviations
BMR
basal metabolic rate
-
BTPS
at body temperature and pressure, saturated
-
oxygen extraction efficiency
-
f
ventilation frequency
-
h
mean coefficient of heat transfer
-
HA
high altitude
-
instantaneous oxygen consumption
-
LA
low altitude
-
RH
relative humidity
-
SMR
standard metabolic rate
-
STPD
standard temperature and pressure, dry
-
T
temperature
-
a
ambient
-
b
body
-
lc
lower critical of thermoneutral zone
-
minute volume
-
V
T
tidal volume 相似文献
17.
Undifferentiated Friend erythroleukemic cells (FL cells) acquire membrane microviscosity (
), in accord with the culture cell density. At low cell density
poise, whereas at confluency it increases to
poise. Concomitantly, the total number of available transferrin receptors per cell decreases by about 80% upon increase in
cell density. Modulation of membrane microviscosity, by artificial alteration of the membrane cholesterol level, mediates
similar modulations of the availability of the transferrin receptors. The correlation between the availability of the transferrin
receptors and the membrane lipid fluidity may take part in the overt decrease in iron uptake by erythroid cells along the
erythropoiesis pathway. 相似文献
18.
Tamir M. Ellis Mark A. Chappell 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1987,157(3):393-402
Summary Thermogenic incubation has been documented in two large species of pythons, but the phenomenon has not been studied in small species with concomitantly large heat transfer coefficients. We describe behavior, metabolic rates, mass changes, and temperature relations for adult ball pythons (Python regius), the smallest member of the genus, during the reproductive cycle. Egg and hatchling metabolism and hatchling growth rates were also examined.Rates of oxygen consumption (
) of both gravid and non-gravid snakes showed typical ectothermic responses to changing ambient temperature (T
a). TheQ
10 forT
a's of 20–35°C was 2.2–2.3. The
of gravid females was significantly greater than that of non-gravid snakes at allT
a. Maximum oxygen consumption (
max) during forced exercise was about 12 times resting
atT
a=30°C.Eggs (5–6 per female) were laid in April. Total clutch mass was approximately 32% of the females' pre-oviposition mass. After oviposition, mother snakes coiled tightly around their clutches and remained in close attendance until the eggs hatched in June. Sudden decreases inT
a elicited abrupt but transient 2- to 4-fold increases in the
of incubating females. Similar responses were not observed in non-incubating snakes. The steady-state
of incubating females was independent ofT
a. In no case was body temperature (T
b) elevated more than a few tenths of a degree aboveT
a in steady-state conditions.The
of developing eggs increased sigmoidally through the 58–70 day incubation period. Total oxygen consumption during incubation atT
a=29.2°C was about 3.61 per egg. Young snakes quadrupled their mass during their first year of growth.Compared to larger python species which are endothermic during incubation, ball pythons have similar aerobic scopes and higher mass-specific
max. However, effective endothermy in ball pythons is precluded by high thermal conductance and limited energy stores. 相似文献
19.
Fumio Yamazaki Nobuharu Fujii Ryoko Sone Haruo Ikegami 《European journal of applied physiology and occupational physiology》1994,69(3):228-232
To evaluate the mechanism of potentiation of sweating after long-term physical training, we compared sweating function in trained and untrained subjects using the frequency of sweat expulsion (f
sw) as an indicator of central sudomotor activity. Nine trained male subjects (trained group) and eight untrained male subjects (untrained group) performed 30-min cycle exercise at 35% maximal oxygen uptake at 25°C ambient temperature and 35% relative humidity. Oesophageal temperature (T
oes), mean body temperature
b, chest sweating rate (
sw,chest), forearm sweating rate (
forearm), andf
sw were measured. The slopes of the
sw,chest versus body temperature (T
oes and
b) and versusf
sw relationships in the trained group were significantly greater than those in the untrained group (both,P < 0.05), while there was no difference between the groups in the slopes of the
sw,chest versus body temperature or versusf
sw relationships. Neither the body temperature threshold for initiation of chest or forearm sweating nor the slope of thef
sw-
b relationship differed between groups. We concluded that, during light exercise at moderate ambient temperature, the
sw,chest in the subjects who had undergone long-term physical training was greater than that in the untrained subjects while the
sw,forearm was not changed. The greater
sw,chest in the trained subjects was concluded to be due to an increase of sensitivity of peripheral mechanisms. 相似文献
20.
J. P. Walsh D. F. Boggs D. L. Kilgore Jr. 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1996,166(6):351-358
The ventilatory and metabolic responses of lesser spear-nosed bats to hypoxia and hypercapnia were measured to determine whether
these corresponded to preliminary allometries and a positive relationship between hypoxic ventilatory threshold andP
50. Ventilatory responses of lesser spear-nosed bats to 3, 5 and 7% CO2 differed significantly from ventilation on air and each other. The magnitude of their ventilatory response to CO2 is consistent with the prediction of a smaller ventilatory response to hypercapnia in small compared to large mammals [
; Williams et al. (1994)]. Among 12, 10 and 8% O2 treatments only the ventilatory response to 8% O2 differed significantly from ventilation on air or the other treatments. Metabolic rate was significantly reduced at both
10 and 8% O2. The hypoxic ventilatory response of these bats does not support the prediction of a greater response in small compared to
large mammals [
; Boggs and Tenney (1984)]. Their metabolic response is consistent with the hypoxic hypometabolism typical of small mammals,
though not of comparable magnitude. The response, expressed as percent change in convection requirement (
), is also less than that observed in other small mammals. This relative insensitivity to hypoxia may be associated with this
bat's unusually high affinity hemoglobin (P50=27.5 torr). 相似文献