Subject: daphnia heart rate

Martine Berube (martine@sbs.bangor.ac.uk)
Mon, 22 Mar 1999 10:47:09 GMT

At 12.51 PM 21-03-1999 +0000, you wrote:
>Hi
>        Please could you explain to me the effect of acetylcholine and
>adrenaline on the heart rate of daphnia. And more information of the
>regulation of the heart beat in daphnia. 
>
>Thanks
>-- 
>nick bhutani
>

Dear Nick,
Here are three articles which might help you with your research. I am afraid
that daphnia is not my field of expertises but I hope that these articles
can help you.
Sincerely,
Martine
_____________________
                        Systemic and metabolic responses in Daphnia magna to
anoxia
                             Paul RJ, Colmorgen M, Pirow R, Chen YH, Tsai MC
 COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR AND INTEGRATIVE PHYSIOLOGY 
                                       120: (3) 519-530 JUL 1998


Abstract:
The anoxic tolerance of the water flea Daphnia magna proved to be
well-developed. During the first 1 or 2 h of anoxia,
perfusion rate was not essentially impeded: admittedly, there was a 30-40%
reduction of the amplitude of heart contractions,
but the heart beat at a rate either similar to normoxia (150 min(-1) at T=15
degrees C) or markedly higher tin more than half
of the experiments). During that period, energy was provided by a high rate
of anaerobic metabolism: L-lactate partly
accumulated in the animals (0.36 mu mol lactate g(-1) FW min(-1)), partly it
was excreted into the medium (0.08 mu mol
lactate g(-1) FW min(-1)). The anaerobiosis was accompanied by a decrease of
intracellular as well as extracellular pH
(metabolic acidosis). A metabolic depression, starting after about 1 or 2 h
of anoxia, helped to prolong survival time during
long-term anoxia (up to 24 h): in many experiments, heart and perfusion rate
sharply declined to a much lower level (well
below the normoxic rate), which was maintained during the next hours of
anoxia. The accumulation of lactate stopped, while
lactate excretion into the medium continued at an unchanged rate. If the
anoxic period exceeded 20 min, long-term recovery
processes, lasting up to 4 h, were found during normoxia: the heart rate
increased and reached a maximum frequently after
40-50 min of recovery. There was also a restoration of pre-anoxic intra- and
extracellular pH values. Additional
experiments on the effects of altered ambient P-CO2/pH on heart rate and
blood pH revealed pH to be a possible control
factor of heart rate. (C) 1998 Elsevier Science Inc. All rights reserved.

Author Keywords:
anoxia, circulation, Daphnia, fluorescent probe, heart, metabolism, pH

KeyWords Plus:
ENERGY-METABOLISM, VENTRICULAR CELLS, GUINEA-PIG, HYPOXIA, CRUSTACEA, PATTERNS,
RECOVERY, LACTATE

Addresses:
Paul RJ, Westfalische Wilhelms Universitat, Inst Zoophysiol, Hindenburgpl
55, D-48143 Munster, Germany.
Westfalische Wilhelms Universitat, Inst Zoophysiol, D-48143 Munster, Germany.
Natl Taiwan Univ, Coll Med, Dept Pharmacol, Taipei 10764, Taiwan.

Publisher:
ELSEVIER SCIENCE INC, NEW YORK

ISSN:
1095-6433 
_________________________

A stroboscopic method to investigate the effect of caffeine on Daphnia heart
rate
                                              Foster R
                              JOURNAL OF BIOLOGICAL EDUCATION 
                                       31: (4) 253-255 WIN 1997

Addresses:
Foster R, Univ Newcastle, Dept Physiol, Newcastle Upon Tyne NE7 7UY, Tyne &
Wear, England.
Kimbolton Sch, Huntingdon PE18 0EA, England.

Publisher:
INST BIOLOGY, LONDON
________________________________

 Circulation and respiratory control in millimetre-sized animals (Daphnia
magna, Folsomia candida) studied by optical methods
                            Paul RJ, Colmorgen M, Huller S, Tyroller F,
Zinkler D
    JOURNAL OF COMPARATIVE PHYSIOLOGY B-BIOCHEMICAL SYSTEMIC AND ENVIRONMENTAL
                                           PHYSIOLOGY 
                                      167: (6) 399-408 AUG 1997


Abstract:
During hypoxia, oxyregulating water-breathers usually control O-2 uptake by
changing ventilatory convection. Using optical
techniques we studied ventilation, circulation and respiratory control in
small animals, a millimetre in size, which were
more or less pronounced oxyregulators (Daphnia magna, Folsomia candida). In
Daphnia we found no adaptive changes in
the ventilatory water flow rate during hypoxia. Frequency and amplitude of
the movements of the thoracic limbs remained
constant during this environmental condition. During anoxia there was a
reduction in both. In contrast to ventilatory
convection, the circulatory blood flow rate adapted to hypoxia. At low
oxygen partial pressures, the heart frequency
strongly increased (compensatory tachycardia) in Daphnia, whereas the stroke
volume remained constant. Accordingly,
there was an increase in cardiac output during hypoxia. Folsomia also showed
a marked increase of heart frequency during
severe hypoxia. The adaptive changes in blood flow rate should help to
maintain sufficient partial pressure differences
between medium, blood and tissues and should help to avoid anoxic zones in
the animal. During anoxia, the heart continued
to beat in Daphnia (at a rate more or less similar to normoxia, but with a
reduced stroke volume) for periods of many hours.
The heart frequency showed typical courses during anoxia and subsequent
normoxia, which are probably related to energy
metabolism.

Author Keywords:
circulation, Daphnia, image processing, optophysiology, respiratory control

KeyWords Plus:
CARCINUS-MAENAS L, ENVIRONMENTAL HYPOXIA, SHORE CRAB, RESPONSES, TEMPERATURES

Addresses:
Paul RJ, UNIV MUNSTER, INST ZOOPHYSIOL, HINDENBURGPLATZ 55, D-48143 MUNSTER,
GERMANY.
UNIV MUNICH, INST ZOOL, D-80333 MUNICH, GERMANY.
RUHR UNIV BOCHUM, LEHRSTUHL TIERPHYSIOL, D-44780 BOCHUM, GERMANY.

Publisher:
SPRINGER VERLAG, NEW YORK

ISSN:
0174-1578 
Martine Berube
School of Biological Sciences 		    
University of Wales - Bangor                
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Gwynedd LL57 2UW 		
Wales, United Kingdom		
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