全 文 ：动　物　学　研　究　1998 ,19(4):269 ～ 276 CN53-1040/Q　ISSN 0254-5853
Zoological Research
EFFECTS OF BODY TEMPERATURE ON
ELECTROCARDIOGRAMS OF LIZARD
Eremias multiocellata ＊
LI Ren-de　CHEN Qiang①　LIU Nai-fa
(Depar tment of Biology , Lanzhou Universi ty , Lanzhou　730001)
Abstract　Electro cardiograms (ECG)of Eremias multiocellata were studied at 5 -35℃ in
body temperature.Electrocardiog ram w ave intervals (R-R , P-R , QRS , T-P , and R-T)shor t-
ened w hile heart rate increased with the increasing of body temperature.The average hear t rate w as
14.6/ min at 5℃, w hereas it was 201/min at 35℃.The duration of wave intervals of ECG and the
heart rate w ere related significantly to the body temperature(P<0.001).Among the components of
a cardiac cycle the cardiac rest period(TP intervals)and the a tria-ventricular conduction time(PR
interval)were affected mostly by body tempera ture.I n the other hand the ventricular depolarization
and repolarization (QRS and R-T interv als)were relatively less affected by the body temperature.
The increasing o f hear t rate with body temperature was mainly caused by the sho rtening o f ECG wave
intervals , and the T-P interval(the cardiac rest period)was sho rtened more noticeably than o ther
intervals.
　　Key words　Eremias multiocellata , Electrocardiog ram , Body temperature
The heart activity of lizards and the relation betw een heart activity and body tempera-
ture have been studied since 1960s(Baytholomew ,1962 , 1963 ,1964;Daw son , 1958 , 1960 ,
1963;Furman , 1960;Licht , 1965;Maynard , 1960;Mullen , 1967).However , most early
w orks w ere focused on the relat ion between heart rate and body/environment temperature.
Porcell(1986)studied the electrocardiogram of lizard Gallot ia gal lot i(body w eight 43-47
g)and reported the pattern that the w ave intervals of ECG varied wi th body temperature and
the characteristic of exci tation conduction in cardiac cycle and discussed the mechanism that
the heart activity varies w ith body temperature.His w ork is of important theo retical signifi-
cance to the mechanism of the variation of electrocardiac activities.However , there is only
one species on which his studies were carried.Thus , further investigations and comparat ive
studies on dif ferent species in different place and dif ferent ecological envi ronment are needed.
　In this paper , we report our w ork conducted on the small ovoviviparous lizard Erem ias
①Corresponding author
＊ This work was supported by a grant f rom Nation Science Foundation of China.
本文 1997-08-01收到 , 1997-12-09修回
multiocel lata (body w eight 5.8-10.2 g)distributed in the desert and semi-desert area in
the northwest of China using the methods adapted from Porcell(1986).The elect rocardio-
g ram was reco rded at different body temperature.The pattern of heart activity variation w ith
body temperature and its adaptation feature to temperature were studied.
1　Materials and Methods
　Fig.1　ECG of Eremias multiocellata at body temperature of 　　
　　　5-35℃
　S tandard voltage:2 mV/ cm , rate of paper movemen t:400 m s/cm.
The 125 lizards used in
this w ork were collected in
Minqin county , Gansu
Province.The average body
weight w as(7.03±1.40)g ,
mean sn - outvent leng th
(SVL)was (60.6 ±4.9)
mm.The lizards w ere kept in
the labo ratory and fed w ith
the worm , Tenebrio moli tor .
The body weight and SV L
were measured before every
ECG recording.They w ere
recorded at 7 body tempera-
ture situations—5 , 10 , 15 ,
20 , 25 , 30 and 35℃, some
individuals w ere reco rded at
40 , 42 , 44 , 45 and 46℃.At
each body temperature situa-
tion , 15 individuals w ere
recorded.The recording of
ECG was carried out in a
thermostat controlled amb -
ient(over room temperature)
o r a thermostat controlled ref rigerator(below room temperature).Animals were bound to a
plate with the back side down and put in the ambient or ref rigerato r about 30 minutes before
recording.The body temperature w as monitored by an electric thermometer(Inst rument of
Beijing Normal University)whose small thermistor probe w as inserted into the animals cloa-
ca 2 cm deep.The recording w as started 5 min after the set temperature was reached.For
each individual the recording last 5-10 min.The records of rest states of animals were cho-
sen for analysis.
The bipolar elect rocardiog ram was recorded by two stainless steel needle elect rodes
270 动　物　学　研　究 19卷
punctured subcutaneously to the right and lef t f ront limbs about 5 mm deep.A third elec-
trode w as inserted to the right hind leg served as earth elect rode.The signal was led to a tw o
channel physiog raph (Chengdu Inst rument Factory)and the electrocardiogram was depicted
onto the record paper.
The duration of the PR , TP , RT , and RR intervals and QRS complex were measured by
a ruler on the record paper.The data w ere processed using statistical methods , and the t-
test w as used to check the signif ication.
Fig.2　Th e relation betw een ECG w ave　　　　　
intervals and body temperature
a.RR;b.RT;c.TP;d.PR interval;　　　　　
e.QRS complex.　　　　　　　　　　　　　　　
2　Results
　The intervals w ere mesured as:R
-T interval or S-T period—from
the end of Q RS to the end of T
w ave;T -P interval—f rom the end
of T w ave to the beginning of P
w ave;P -R interval—from the be-
ginning of P w ave to the beginning
of QRS.
　The segments of electrocardio-
g ram of number 2 lizard(w:7.61 g ,
SVL :65.5 mm)at 7 body tempera-
ture situations in the range 5-35℃
were show n in Fig .1.The P w ave
w as of very low relative altitude and
posit ive.The T wave w as also posi-
tive and its altitude w as higher than
P w ave.The voltage of P w as 0.027
-0.053 mV and most ly appeared
when body temperature ranged from
5 to 20℃.When body temperature
w as over 25℃ the T and P w ere al-
most overlapping in most animals ECG , and dif ficult to be recognized.The Q wave w as very
small , and usually could not be seen.The S w ave w as negative and appeared at temperature
over 15℃.
The voltage of w aves is given in Table 1.
The relationship between each interv al duration and body temperature was calculated by
corresponding reg ression.The regression equation are
RR(ms)=5026e-0.0852T 　　(r=-0.9863　P <0.0001)
　　PR(ms)=1411e-0.0891T 　　(r=-0.9906　P <0.0001)
2714期 李仁德等:温度对密点麻蜥心电活动的影响(英文)
　　RT(ms)=2239e-0.0820T 　　(r=-0.9985　P <0.0001)
　　TP(ms)=1584e-0.1149T 　　(r=-0.9713　P <0.0001)
　　QRS(ms)=122e-0.0412T 　　(r=-0.9452　P<0.001)
Table 1　Voltage(mV)of ECG waves at different
body temperature
Body temper-
ature/ ℃
P w ave
x±SD
T w ave
x ±SD
R w ave
x±SD
5 0.027±0.011 0.099±0.022 0.199±0.064
10 0.041±0.016 0.120±0.053 0.240±0.062
15 0.036±0.011 0.108±0.036 0.273±0.037
20 0.035±0.013 0.144±0.077 0.327±0.098
25 0.048±0.013 0.156±0.075 0.303±0.063
30 0.053±0.005 0.194±0.089 0.3487±0.096
35 0.050±0.001 0.187±0.073 0.513±0.103
　　Fig.2 is the curves derived f rom the regression equations above , showing the variation
of interval duration to body temperature.The interval durations decreased exponentially w ith
body temperature increasing , and the co rrespondence w as very significant(P <0.001).For
searching the mechanism of the increase of heart rate w ith the increasing of body tempera-
ture , the variation of the relative values of every periods w as show n by the regression equa-
tions below :
　　Fig.3　The relation betw een the
　　　　relative value of wave inter-
　　　　vals and body temperature
　　　　　a.RT/RR;b.PR/RR;
　　　　　c.TP/ RR;d.Q RS/RR.
QRS/RR(%)=1.037 +0.2697 T 　(r =
0.9661　P <0.001)
RT/RR(%)=45.12 +0.1334 T 　(r =
0.2606　P <0.25)
TP/RR(%)=29.86 -0.5397 T 　(r =
-0.7513　P<0.025)
PR/RR(%)=28.28 -0.1099 T 　(r =
-0.3422　P<0.1)
　Fig .3 w as derived from these equations.QRS/
RR was significant ly correlated w ith body temper-
ature (r =9.9661 , P <0.001) ranged from
2.39% to 10.48%over the body temperature ran
-ge 5-35℃.The correlation betw een RT/RR
and body temperature w as also positive but no t
significant (r =0.2606;P <0.25), RT/PT
ranged from 45.79% to 49.79% over the body
temperature range.Yet TP/ RR and PR/RR were
correlated negatively to body temperature.The TP/RR co rrelation w as significant (r =
-0.7513;P <0.05)and PR/RR correlat ion w as not(r=-0.3422 , P <0.01).TR/RR
272 动　物　学　研　究 19卷
ranged from 27.16% to 11.24%, PR/RR from 27.73%to 24.43%over the body temper-
ature range 5-35℃.
Table 2　Comparison of heart rate of different lizard species at body temperature of 35℃
Species Weight/ g Heart rate(beat/min) Literature
Amphibolurum barbatus 300-500 61-86 Bartholomew , 1963
Ti liqua rugosa 400 62 Licht , 1965
Gal lot ia gal lot i 43-47 133 Porcell , 1986
Crotaphytus collari s 25-35 120 Daw son , 1963
Phrynocephalus prz ewalski i 4.6-9.5 244.9 Li , 1992
E remias mul tiocellata 5.8-10.2 201 This paper
3　Discussion
　　Fig.4　ECG of Eremias multiocellata at high body
　temperature (40-45℃)
Standard voltage:2 mV/cm ,
rate of paper movement:400 ms/ cm .
At the same body tem-
perature 35℃, the heart rate
of Eremias mult iocellata was
notably higher than that of
most lizard species reported
(Table 2).Licht (1965)re-
po rted the relation between
the heart rate and body we-
ight is R = 153Wt -0.267.
Generally the greater the
w eight , the lower the heart
rate , However , the heart rate
of Gal - lot ia gallot i was
higher than C. collaris
whose body wei -ght was
lower.The body we-ight of E .multiocellata is similar to that of P.przewalskii , but the
heart rates were quite different.These may be at t ributed to the ecological environment as
w ell as taxonomic status.The speciation is the result of evolution and the adaptation to the
environment.The adaptation can affect many physical aspects of species.G.gal lot i lives in
the Canary Island and C.col laris lives in the arid , semi-arid zone in North America.Still ,
E .multiocellata lives in bush clumps in semi-desert region , so that it s home range is rela-
tively small and it does not move a lot.how ever , P .przewalsk ii lives on broad sand ground ,
where there is less vegetation , so that its home range is much larger and it moves more than
E .multiocellata.
In the experiment , we recorded the ECG of some individuals at high temperature , and
the results were show n in Fig.4.At 40℃, the heart rate was a litt le slow er than at 35℃,
2734期 李仁德等:温度对密点麻蜥心电活动的影响(英文)
but the w ave w as basically normal.At 42℃the heart rate was notably slow er and the height
of R and T w ave were notably low er than at 35℃.When body temperature reached 44℃
ECG became abnormal—T w ave disappeared , R wave w as very small and RR interval be-
came irregular.When body temperature reached 45℃ or 46℃ ECG disappeared , the heart
stopped and the lizards died.This result w as coincident wi th the reported lethal high temper-
ature of this species(Li , 1992).
Over the body temperature range 5-35℃, the duration of every w ave interval of ECG
decreased wi th the increase of body temperature.This result ag reed to the result of Porcel
(1986)on G.gal lot i.The relative values QRS/RR and RT/ RR correlated positively ,
whereas TP/RR correlated negatively w ith body temperature.This indicated that dif ferent
part of the cardiac cycle w as affected differently by body temperature.When body tempera-
ture going up , the cardiac rest period (TP interval)and the atria-ventricular conduction
time(PR interval)were relatively shortened , but the duration of vent ricular depolarization
and repolarization (RT interval)prolonged.This meant that the increase of heart rate of
Eremias mul tiocel lata was caused by the shortening of rest period and acceleration of at ria-
ventricular conduction.The Shortening of rest period w as the major factor.
Comparing the w ave interv als of ECG of G.galloti , P .przeovalskii (Li Rende , 1992)
w ith those of E.multiocellata ,we found that for G.galloti the relat ion was TP >PR>
RT >QRS , whereas for E.multiocel lata and P .przewalskii it w as RT >TP >PR>QRS.
In other wo rds , for G.galloti TP interval w as the longest part of ECG ,but for P .prze-
walski i and E .mult iocellata the longest interval w as RT .This meant that at same body
temperature the relative value of cardiac rest period (TP)of G.gal lot i was longer but the
period of vent ricular elect ric events(RT)was shorter than that of E.mutiocel lata and P .
przewalski i.The heart rate of E .mult iocel lata or P.przewalski i , both of w hich have
very low body weight , was higher than that of G.gal lot i.Possibly this make cardiac rest
period relatively shorter in the cardiac cycle.
References
Bartholomew G A ,Hudson J W ,Howell T R , 1962.Body temperature , oxygen consumption , evaporative w ater
loss , and heart rate in the poor-w ill.Condor , 64:117-25.
Bartholomew G A , Tucker V A , 1963.Control of changes in body temperature ,metabolism , and circulation by
the agamid lizard , Amphibolurus barbatus.Physiol.Zool.,36:199-218.
Bartholomew G A , 1964.Size , body temperature , thermal conductance , oxygen consumption , and hear t rate in
Australian varanid lizards.Physiol.Zool., 37:341-354.
Daw son W R ,Bar tholomew G A , 1958.Metabolic and cardiac responses to temperature in the lizard Dipsosaurus
dorsalis.Physiol.Zool.,31:100-111.
Daw son W R ,1960.Physiological responses to temperature in the lizard Eumeces obsoletus.Physiol.Zool .,33:
87-103.
Daw son W R ,Templeton J R , 1963.Physiological responses to temperature in the lizard Crotophytus collaris.
274 动　物　学　研　究 19卷
Physiol.Zool., 36:219-236.
Furman K I ,1960.The electrocardiog ram of the South African clawed toad(Xenopus leavis)w ith special refer-
ence to temperature effects.So.Afr.J .Med.Sci ., 25:109-118.
Li Rende , 1992.Effects of temperature on cardiac activities in the deser t lizard , Phrynocephalus przewalsk ii.
Acta Zoologica Sinica , 38(1):42-47.(in Chinese w ith English summery)
Li Rende , 1992.The influence of environmental temperature on body temperature of Phrynocephalus przewalskii
and Eremias multiocellata and their selection of environmental temperature.Zoological Research ,13(1):47
-52.(in Chinese w ith Eglish summery)
Licht P ,1965.Effects of temperature on hear t rates of lizards during rest activity.Physiol.Zool., 38:129-
137.
Maynard D M , 1960.Heart rate and body size in the spiny lobster.Physiol.Zool., 33:241-251.
Mullen R K ,1967.Comparative electrocardiograph of the Squamata.Physiol.Zool., 40:114-126.
Porcell L D V , 1986.Cardiac responses to temperature in the lizard Gallotia galloti.Comp .Biochem .Physi-
ol.,85A(2):389-394.
温度对密点麻蜥心电活动的影响*
李仁德　陈　强①　刘晒发
(兰州大学生物系　730000)
摘　要　采用甘肃省民勤县荒漠半荒漠环境中的卵胎生蜥蜴密点麻蜥(Eremias mutio-
cellata)为材料 ,研究其心电活动随体温变化的规律以及对环境温度的适应特点。共记录密点
麻蜥 125只 ,每只蜥蜴记录 5 、10 、15 、20 、25 、30 、35℃7个温度等级 ,每个等级 15 ～ 20只;少数
蜥蜴记录的温度范围扩展到 40 、42 、44 、45和 46℃。环境温度采用由电接点温度计和继电器
控制的电冰箱和恒温箱来控制。体温测量采用 SY-2型数字式温度计 ,测定时插入泄殖腔 2
cm 。心电描记采用 LMS2B型二道生理记录仪。电极为不锈钢针形电极。实验前将蜥蜴放入
待测温度环境中适应 2 h。被测蜥蜴背位固定于木板上 ,不麻醉 ,将记录电极的正极插入左前
肢皮下 ,负极插入右前肢皮下 ,地线插入后肢皮下 ,插入深度均为 5 mm 。电极固定后待蜥蜴
的体温达到预定温度 5 min后再开始心电记录。在实验记录纸上测量各波的电压值及各间期
的时间 ,其中 R～ T间期即 S ～ T 段 ,表示从 QRS 波结束到 T 波结束的时间 ,T ～ P间期表示从
T 波结束到 P波开始时的时间 ,P ～ R间期表示从 P波开始到 QRS波开始的时间 ,以 t 测验检
验相关系数的显著性。
体温为 5 ～ 35℃时的心电图中 P波和 T 波是正向的 ,且幅度很低 ,R波幅度高于 P波和 T
波。P波电压值为 0.027 ～ 0.0525 mV ,多在 5 ～ 25℃时出现 ,高体温(25℃以上)时大多数蜥蜴
心电图上 P波和 T 波重叠 ,不易分辨。Q 波很小 ,大多不易辨认 , S 波在 15℃以上时均可出
现 ,且为负向波。体温由 5℃上升至35℃时 ,心率由 14.6次/min增加为 201次/min。P～ R、R
～ T 和 T ～ P间期的值都随之缩短。各间期值在各温度等级之间的差异都极显著(P <0.
001)。在相同体温条件下 ,密点麻蜥的心率范围较一些作者报道的其他蜥蜴的心率都快 ,且
差别很大。心率和体重之间有 R =153 Wt0.207的关系(Licht , 1965),密点麻蜥的体重小则心
率快 ,但是密点麻蜥(E.multiocellata)和荒漠沙蜥(Phrynocephalus przewalskii)的体重相似 ,
心率却有差异 ,除种属差异外 ,也与生态环境的差异有关。
2754期 李仁德等:温度对密点麻蜥心电活动的影响(英文)
QRS/RR和 RT/RR的值与体温呈正相关 ,而 TP/RR和 PR/RR的值与体温呈负相关。
说明在体温升高时心动周期中各间期缩短的程度不同 ,即心脏的静息期(TP)和房室传导时间
(PR)相对缩短 ,而心室开始去极化至复极化结束的时间(QRS 和 RT)相对延长。这一特征说
明了密点麻蜥的心率随体温升高而加快的原因是静息期缩短和房室传导速度加快 ,而静息期
缩短是最重要的因素。
关键词　密点麻蜥 ,心电图 ,体温
中图分类号　Q959.62
*国家自然科学基金资助项目
①通讯联系人
276 动　物　学　研　究 19卷