[Noncholinergic inhibition is the cause of differences in the heart rate in well-nourished and malnourished rats].
The postnatal development of heart rate was compared in rats from average litters (7-10 animals) and from oversize litters (15-18 animals). Rats from oversize litters were found to have a higher heart rate between the 25th and 45th day of life compared to animals from average litters. Over the further developmental period the difference kept decreasing to disappear completely at the age of 85 days. The difference was observed also in animals which received high doses of atropine and metipranolol and is thus not attributable to difference in the tonic influence of adrenergic and cholinergic innervation. Transmural stimulation of the sinoatrial node region in isolated atria allows to demonstrate the negative chronotropic effect in young animals from average litters. This noncholinergic inhibition was not observed in animals from oversized litters and in adult animals of both groups. It was blocked by theophylline in the majority of cases. All the observed findings can be explained in the light of noncholinergic inhibition of the sinoatrial node which is tonically effective in young animals from average litters and disappears in adulthood.
Vlk
J
J
Katedra fyziologie lékarské fakulty UK v Plzni, Plzen.
Jánská
E
E
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D014290:Metipranolol / Q000494:pharmacology; D009433:Neural Inhibition; D009748:Nutrition Disorders / Q000503:physiopathology*; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000502:physiology; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000502:physiology; D012849:Sinoatrial Node / Q000503:physiopathology*; D013806:Theophylline / Q000494:pharmacology
D011943:Receptors, Adrenergic, beta; D011976:Receptors, Muscarinic; D001285:Atropine; D013806:Theophylline; D014290:Metipranolol
Necholinergní inhibice je prícinou rozdílu v srdecní frekvenci dobre zivených a podvyzivených potkanů.