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Effect of training on aerobic capacity and temperature regulation in pelt sheep exposed to treadmill exercise
S86 P5-8
P5-10
Developmental changes in dopamine modulation of the heartbeat in the isopod crustacean Ligia exotica
Crustacean cardioactive peptide-immunoreactive neurons identified in the nervous system of Artemia salina and Daphnia magna (Crustacea: Anostraca and Cladocera).
Yamagishi H Institute of Biological Sciences, University of Tsukuba, Tsukuba, ibiaraKi 305.8572, .Japan.
Zhang Q and Dircksen H Institut ftir Zoophysiologie, Rheinische Friedrich-Wilhelms Universittit, Endenicher Allee 1 l-l 3, D-53 115 Bonn, Germany
The heart pacemaker of Ligia exotica is trasferred from the cardiac muscle to the cardiac ganglion during juvenile development. Developmental changes in the effects of dopamine known as one of the neurohormons released from the crustacean pericardial organ on the heartbeat of L,igiu exotica. In the myogenic heart of early juveniles, dopamine decreased the frequency of the action potential and increased the amplitude and duration of the action potential plateau of the cardiac muscle in a concentration dependent manner. These effects resulted in negative chronotropic and positive inotropic effects on the myogenic heartbeat of early juveniles. On the other hand, in the neurogenic hearts of late juveniles and adults, dopamine increased the frequency of bursting activity of the cardiac ganglion and increased the amplitude and duration of the action potential plateau of the cardiac muscle in a concentration dependent manner. These effects resulted in positive chronotropic and positive inotropic effects on the neurogenic heartbeat of late juveniles and adults. Thus, the chronotropic effect of dopamine on the heartbeat changed from negative to positive in association with the transfer of the heart pacemaker from the cardiac muscle to the cardiac ganglion during juvenile development.
Crustacean cardioactive peptide (CCAP), a phylogenetically old arthropod neuropeptide first discovered in the crab Curcinus maenus, has been immunolocalized in distinct neurons of the nervous systems of the entomostracans Artemia sulina and Duphniu magna. Neurons were reconstructed completely from PAP-stained CNS whole mounts and sections. In Artemiu, two clusters of CCAP-ir interneurons occur in the brain and 12 ventral nerve cord segments contain one pair of CCAP-ir neurones, whereas the entire CNS of Duphniu shows merely two CCAP-ir neurones restricted to the suboesophageal ganglia, branches of which ascend into the brain and descend into peripheral nerves passing by the hindgut. All these neurons are similar to CCAP neuron types in decapods. No evidence was found for an association of any these neurons with a X-organ-sinus-gland system or other neurohemal organs known from decapods. Preabsorption controls indicate the existence of authentic CCAP or a closely related peptide in both species. The morphology of these putative peptidergic neurons identified for the first time in entomostracans suggests that CCAP may act as a neuromodulatory peptide and/or neurohormone serving much the same fimctions as in decapods but in phylogenetically distant crustacean orders. P6-1
P5-9
A CH-like
peptide
the crayfish Yazawa
purified
enhances
from the sinus
cardiac
gland
of
performance.
T, Ohoka T, Kuwasawa
K, Aizawa S, Isida M,
Ezure T and Shibata M Department
of Biological
Effect of training on aerobic capacity and temperature regulation in pelt sheep exposed to treadmill exercise.
Sciences,
Tokyo
Metropolitan
Aulie A, Sjaastad 0V and Hove K Department of Biochemistry, Physiology and Nutrition, Norwegian College of Veterinary Medicine, P.O.Box 8146 Dep. N-0033 Oslo, Norway and Department of Animal Science, Agricultural University of Norway, N-1432 As, Norway.
University, Hachioji, Tokyo 192-0397, Japan Crustacean
hyperglycemic
hormone (CH) has been purified
from the sinus gland of Orconectes muenus
(Keller et al. 1985).
limosus
and Carsinus
We have extracted, from the
sinus gland of Procumburus clurkii, a hyperglycemic peptide having 72 amino acid residues and a molecular weight of 8,700 dalton. This peptide resembles CH in molecular weight, amino acid composition,
and hormonal activity. We have designated
it “CH-like peptide” (CH-LP).
CH-LP ( lO-6 M) accelerated
and augmented contractions of the crayfish heart. The effects were comparable proctolin.
to those of another cardio-active
CH-LP activates
a cGMP-producing
peptide, enzyme,
guanylyl cyclase, in a membrane preparation from a mixture of the crayfish
myocardium
and cardiac ganglion,
proctolin did not stimulate this enzyme.
although
In untrained sheep, body temperature (Tb) and blood lactate (LA) increases markedly during exercise. The effect of 1 month of intense training was tested on pelt sheep, running on a treadmill. During the tests (before and after the training period), the ambient temperature was 16-19 ‘C. Arterial blood was sampled and T, measured before and after 5 min exercise at 1.8,2.8 and 3.8 m/s. The sheep was allowed a 5 min rest between each speed. After the last run,Tb was 41.3 “C, or 1.4 “C above resting level in both tests, while LA increased from 2.1 to 24.0 mmolil in untrained sheep and from 1.3 to only 8.1 mmol/l in the trained. The elevated LA was reflected in both the pH and [HCO3-] in arterial blood. In the untrained, pH decreased from 7.47 to 7.28 and [HC03-3 from 25.5 to 10.5 mmol/l and in the trained, from 7.39 to 7,35 and from 26.2 to 16.5 mmolil, respectively. Since arterial Pcoz decreased after both tests, to 3.0 kPa in the untrained and to 3.9 kPa in the trained, respiratory compensation have taken place. In conclusion, training improves the aerobic capacity but not the temperature regulation in exercising sheep.
P5-10
Developmental changes in dopamine modulation of the heartbeat in the isopod crustacean Ligia exotica
Crustacean cardioactive peptide-immunoreactive neurons identified in the nervous system of Artemia salina and Daphnia magna (Crustacea: Anostraca and Cladocera).
Yamagishi H Institute of Biological Sciences, University of Tsukuba, Tsukuba, ibiaraKi 305.8572, .Japan.
Zhang Q and Dircksen H Institut ftir Zoophysiologie, Rheinische Friedrich-Wilhelms Universittit, Endenicher Allee 1 l-l 3, D-53 115 Bonn, Germany
The heart pacemaker of Ligia exotica is trasferred from the cardiac muscle to the cardiac ganglion during juvenile development. Developmental changes in the effects of dopamine known as one of the neurohormons released from the crustacean pericardial organ on the heartbeat of L,igiu exotica. In the myogenic heart of early juveniles, dopamine decreased the frequency of the action potential and increased the amplitude and duration of the action potential plateau of the cardiac muscle in a concentration dependent manner. These effects resulted in negative chronotropic and positive inotropic effects on the myogenic heartbeat of early juveniles. On the other hand, in the neurogenic hearts of late juveniles and adults, dopamine increased the frequency of bursting activity of the cardiac ganglion and increased the amplitude and duration of the action potential plateau of the cardiac muscle in a concentration dependent manner. These effects resulted in positive chronotropic and positive inotropic effects on the neurogenic heartbeat of late juveniles and adults. Thus, the chronotropic effect of dopamine on the heartbeat changed from negative to positive in association with the transfer of the heart pacemaker from the cardiac muscle to the cardiac ganglion during juvenile development.
Crustacean cardioactive peptide (CCAP), a phylogenetically old arthropod neuropeptide first discovered in the crab Curcinus maenus, has been immunolocalized in distinct neurons of the nervous systems of the entomostracans Artemia sulina and Duphniu magna. Neurons were reconstructed completely from PAP-stained CNS whole mounts and sections. In Artemiu, two clusters of CCAP-ir interneurons occur in the brain and 12 ventral nerve cord segments contain one pair of CCAP-ir neurones, whereas the entire CNS of Duphniu shows merely two CCAP-ir neurones restricted to the suboesophageal ganglia, branches of which ascend into the brain and descend into peripheral nerves passing by the hindgut. All these neurons are similar to CCAP neuron types in decapods. No evidence was found for an association of any these neurons with a X-organ-sinus-gland system or other neurohemal organs known from decapods. Preabsorption controls indicate the existence of authentic CCAP or a closely related peptide in both species. The morphology of these putative peptidergic neurons identified for the first time in entomostracans suggests that CCAP may act as a neuromodulatory peptide and/or neurohormone serving much the same fimctions as in decapods but in phylogenetically distant crustacean orders. P6-1
P5-9
A CH-like
peptide
the crayfish Yazawa
purified
enhances
from the sinus
cardiac
gland
of
performance.
T, Ohoka T, Kuwasawa
K, Aizawa S, Isida M,
Ezure T and Shibata M Department
of Biological
Effect of training on aerobic capacity and temperature regulation in pelt sheep exposed to treadmill exercise.
Sciences,
Tokyo
Metropolitan
Aulie A, Sjaastad 0V and Hove K Department of Biochemistry, Physiology and Nutrition, Norwegian College of Veterinary Medicine, P.O.Box 8146 Dep. N-0033 Oslo, Norway and Department of Animal Science, Agricultural University of Norway, N-1432 As, Norway.
University, Hachioji, Tokyo 192-0397, Japan Crustacean
hyperglycemic
hormone (CH) has been purified
from the sinus gland of Orconectes muenus
(Keller et al. 1985).
limosus
and Carsinus
We have extracted, from the
sinus gland of Procumburus clurkii, a hyperglycemic peptide having 72 amino acid residues and a molecular weight of 8,700 dalton. This peptide resembles CH in molecular weight, amino acid composition,
and hormonal activity. We have designated
it “CH-like peptide” (CH-LP).
CH-LP ( lO-6 M) accelerated
and augmented contractions of the crayfish heart. The effects were comparable proctolin.
to those of another cardio-active
CH-LP activates
a cGMP-producing
peptide, enzyme,
guanylyl cyclase, in a membrane preparation from a mixture of the crayfish
myocardium
and cardiac ganglion,
proctolin did not stimulate this enzyme.
although
In untrained sheep, body temperature (Tb) and blood lactate (LA) increases markedly during exercise. The effect of 1 month of intense training was tested on pelt sheep, running on a treadmill. During the tests (before and after the training period), the ambient temperature was 16-19 ‘C. Arterial blood was sampled and T, measured before and after 5 min exercise at 1.8,2.8 and 3.8 m/s. The sheep was allowed a 5 min rest between each speed. After the last run,Tb was 41.3 “C, or 1.4 “C above resting level in both tests, while LA increased from 2.1 to 24.0 mmolil in untrained sheep and from 1.3 to only 8.1 mmol/l in the trained. The elevated LA was reflected in both the pH and [HCO3-] in arterial blood. In the untrained, pH decreased from 7.47 to 7.28 and [HC03-3 from 25.5 to 10.5 mmol/l and in the trained, from 7.39 to 7,35 and from 26.2 to 16.5 mmolil, respectively. Since arterial Pcoz decreased after both tests, to 3.0 kPa in the untrained and to 3.9 kPa in the trained, respiratory compensation have taken place. In conclusion, training improves the aerobic capacity but not the temperature regulation in exercising sheep.