Sex differences in mouse heart rate and body temperature and in their regulation by adenosine A1 receptors.
OBJECTIVE
To examine cardiac function, body temperature and locomotor behaviour in the awake adenosine A(1) receptor knock out mouse of both sexes.


METHODS
Male and female A(1)R (+/+) and (-/-) mice, instrumented with telemetric devices, were recorded during basal conditions and after drug administration.


RESULTS
Female mice had higher heart rate, body temperature and locomotion, both during daytime and during the night. Awake A(1)R (-/-) mice had a slightly elevated heart rate, and this was more clear-cut in males. Heart rate was also higher in Langendorff-perfused denervated A(1)R (-/-) hearts. Body temperature was higher in A(1)R (-/-) males and females; locomotor activity was higher in A(1)R (-/-) females, but not in males. The adenosine receptor agonist R-PIA (0.2 mg kg(-1)) decreased heart rate and body temperature, but less in A(1)R (-/-) animals than in A(1)R (+/+) mice (P < 0.001 in both parameters). The unselective adenosine receptor antagonist caffeine had a minor stimulatory effect on heart rate in lower doses, but depressed it at a dose of 75 mg kg(-1). Body temperature was increased after a low dose (7.5 mg kg(-1)) of caffeine in both sexes and genotypes, and markedly reduced after a high dose (75 mg kg(-1)) of caffeine. An intermediary dose of caffeine 30 mg kg(-1) increased or decreased body temperature depending on genotype and sex. Locomotor responses to caffeine were variable depending both on genotype and sex.


CONCLUSIONS
Thus, the adenosine A(1) receptor is involved in the regulation of heart rate, body temperature and locomotor activity, but the magnitude of the involvement is different in males and females.
Yang
J-N
JN
Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
Tiselius
C
C
Daré
E
E
Johansson
B
B
Valen
G
G
Fredholm
B B
BB
D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001831:Body Temperature / Q000187:drug effects / Q000502:physiology*; D002110:Caffeine / Q000494:pharmacology; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D005260:Female; D005838:Genotype; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D008124:Locomotion / Q000187:drug effects / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018696:Neuroprotective Agents / Q000494:pharmacology; D043682:Receptor, Adenosine A1 / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D012727:Sex Characteristics
D000697:Central Nervous System Stimulants; D018696:Neuroprotective Agents; D043682:Receptor, Adenosine A1; C047235:N-(1-methyl-2-phenylethyl)adenosine; D002110:Caffeine; D000241:Adenosine