The effects of adenosine and adenine nucleotides on haemolymph velocity and on heart rate and scaphognathite frequency were investigated in the American lobster Homarus americanus. The infusion of 0.25-2.4 nmol g(−1) min(−1) adenosine produced steady-state concentrations of 2–3 micromol l(−1) adenosine and approximately 80 micromol l(−1) inosine in the haemolymph. No hanges in haemolymph concentration of AMP, hypoxanthine, xanthine or IMP were observed. Adenosine increases haemolymph velocity in the sternal artery from 55+/−29 to 204+/−53 mm s(−1) and in the posterior aorta from 21+/−7 to 54+/−28 mm s(−1)and reduces haemolymph velocity in the lateral arteries from 98+/−92 to 74+/−69 mm s(−1). Heart rate is increased from 69.3+/−7.4 to 81.2+/−6.2 beats min(−1) and scaphognathite frequency from 86.9+/−29.0 to 147.1+/−35.0 beats min(−1). The effects of adenosine are rapidly reversed after the cessation of the infusion of this purine. The adenylates cause similar but lesser changes and the effects are protracted, probably because of low in vivo activities of nucleotidases.

REFERENCES

Arch
J. R. S.
,
Newsholme
E. A.
(
1978
).
Activities and some properties of 5-nucleotidase, adenosine kinase and adenosine deaminase in tissues from vertebrates and invertebrates in relation to the control of the concentration and physiological role of adenosine.
Biochem. J
174
,
965
–.
Beltz
B. S.
,
Kravitz
E. A.
(
1986
).
Aminergic and peptidergic neuromodulation in Crustacea.
J. Exp. Biol
124
,
115
–.
Böhm
M.
(
1987
).
Kardiale Wirkungen von Adenosin: Wirkungsmechanismus, pathophysiologische und klinische Bedeutung.
Klin. Wochenschr
65
,
487
–.
Burnstock
G.
(
1996
).
Purinoceptors: Ontogeny and phyllogeny.
Drug Dev. Res
39
,
204
–.
Butler
P. J.
,
Taylor
E. W.
,
McMahon
B. R.
(
1978
).
Respiratory and circulatory changes in the lobster Homarus vulgaris during long term exposure to moderate hypoxia.
J. Exp. Biol
73
,
131
–.
Carr
W. E. S.
,
Gleeson
R. A.
,
Ache
B. W.
,
Milstead
M. L.
(
1986
).
Olfactory receptors of the spiny lobster: ATPase-sensitive cells with similarities to P2-type purinoceptors of vertebrates.
J. Comp. Physiol
158
,
331
–.
Chauveau
M.
,
Levy
B.
,
Dessanges
J. F.
,
Savin
E.
,
Bailliart
O.
,
Martineaud
J. P.
(
1985
).
Quantitative Doppler blood flow measurements: method and invivo calibration.
Cardiovasc. Res
19
,
700
–.
Chiba
S.
,
Himori
N.
(
1975
).
Different inotropic responses to adenosine an artrial and ventricular muscle of the dog heart.
Jap J. Pharmacol
25
,
489
–.
Depledge
M. H.
(
1984
).
Photoplethysmography — a non-invasive technique for monitoring heart beat and ventilation rate in decapod crustaceans.
Comp. Biochem. Physiol
77
,
369
–.
Deussen
A.
,
Barding
B.
,
Schrader
J.
(
1993
).
Formation and salvage of adenosine by macrovascular endothelial cells.
Am. J. Physiol
264
,
692
–.
Drury
A. N.
,
Szent-Györgyi
A.
(
1929
).
The physiological activity of adenine compounds with special reference to their action upon the mammalian heart.
J. Physiol. Lond
68
,
213
–.
Gerlach
E.
,
Deuticke
B.
,
Dreisbach
R. H.
(
1963
).
Der Nukleotid-Abbau im Herzmuskel bei Sauerstoffmangel und seinemögliche Bedeutung fur die Coronardurchblutung.
Naturwissenschaften
50
,
228
–.
Kravitz
E. A.
(
1988
).
Hormonal control of behaviour: Amines and the biasing behavioural output in lobsters.
Science
241
,
175
–.
Kuramoto
T.
,
Ebara
A.
(
1984
).
Neurohormonal modulation of the cardiac outflow through the cardioarterial valve in the lobster.
J. Exp. Biol
111
,
123
–.
McMahon
B. R.
(
1999
).
Intrinsic and extrinsic influences on cardiac rhythms in crustaceans.
Comp. Biochem. Physiol
124
,
539
–.
Möser
G. H.
,
Schrader
J.
,
Deussen
A.
(
1989
).
Turnover of adenosine in plasma of human and dog blood.
Am. J. Physiol
256
,
779
–.
Morris
S.
,
Bridges
C. R.
,
Grieshaber
M. K.
(
1985
).
A new role for uric acid: Modulator of haemocyanin oxygen affinity in crustaceans.
J. Exp. Zool
235
,
135
–.
Reiber
C. L.
,
McMahon
B. R.
,
Burggren
W.
(
1997
).
Cardiovascular functions in two macruran decapod crustaceans (Procambarus clarkii and Homarus americanus) during periods of inactivity, tail flexion and cardiorespiratory pauses.
J. Exp. Biol
200
,
1103
–.
Rubio
R.
,
Berne
R. M.
,
Dobson
J. G.
Jr.
(
1973
).
Sites of adenosine production in cardiac and skeletal muscle.
Am. J. Physiol
225
,
938
–.
Sedaa
K. O.
,
Bjur
R. A.
,
Shinozuka
K.
,
Westfall
D. P.
(
1990
).
Nerve and drug-induced release of adenine nucleosides and nucleotides from rabbit aorta.
J. Pharmacol. Exp. Ther
252
,
1060
–.
Truchot
J. P.
(
1980
).
Lactate increases the oxygen affinity of crab haemocyanin.
J. Exp. Zool
214
,
205
–.
Wilkens
J. L.
,
Wilkens
L. A.
,
McMahon
B. R.
(
1974
).
Central control of cardiac scaphognathite pacemakers in the crab, Cancer magister.J.
Comp. Physiol
90
,
89
–.
Wilkens
J. L.
,
Mercier
A. J.
,
McMahon
B. R.
(
1985
).
Cardiac and ventilatory responses to stress and to neurohormonal modulators by the shore crab, Carcinus maenas.
Comp. Biochem. Physiol
82
,
337
–.
Wilkens
J. L.
,
Kuramoto
T.
(
1998
).
Comparison of the roles of neurohormones in the regulation of blood distribution from the hearts of American and Japanese lobsters.
J. Comp. Physiol
168
,
483
–.
Zeis
B.
,
Nies
A.
,
Bridges
C. R.
,
Grieshaber
M. K.
(
1992
).
Allosteric modulation of haemocyanin oxygen affinity by L-lactate and urate in the lobster Homarus vulgaris. I. Specific and additive effects on haemocyanin oxygen affinity.
J. Exp. Biol
168
,
93
–.
Zimmermann
H.
(
1992
).
5-nucleotidase: Molecular structure and functional aspects.
Biochem. J
285
,
345
–.
This content is only available via PDF.