G proteins-coupled signaling pathways appear to play a role in the development of cardiac hypertrophy and its progression to heart failure. The present study aimed to investigate trimeric G proteins and adenylyl cyclase signaling in immature as well as in adult rat myocardium during this process caused by pressure overload. Pressure overload was induced in newborn (2-day-old) rats by abdominal aortic banding and myocardial preparations from left ventricular myocardium of immature (10-day-old) and adult (90-day-old) animals were analyzed for the relative content of different G protein subunits and adenylyl cyclase (AC) by immunoblotting with specific antibodies. A functional status of the AC signaling system was also evaluated. Normal maturation of rat heart was accompanied by increased expression of AC type V/VI and VII and of the long isoform (G(s)alphaL) of G(s)alpha protein. In parallel, the amounts of myocardial G(i)alpha/G(o)alpha proteins tended to decrease, and G(q)alpha/G(11)alpha and Gbeta did not change. Interestingly, whereas fluoride-stimulated AC activity increased in the course of maturation, activity of AC measured under other experimental conditions (stimulation by Mn2+, forskolin or isoproterenol) was lower in adult than in young rat myocardium. Pressure overload did not influence distribution of G proteins in immature myocardium, but considerably decreased the content of G(s)alphaL and increased G(o)alpha proteins in hearts of 90-day-old rats. These hearts exhibited worsened functional reserve as compared to age-matched controls and activity of AC was also markedly lower. A considerable reduction in Mn(2+)-stimulated AC activity together with similar decrease in AC activity determined under other stimulation conditions suggests that it is a function of AC catalytic subunit that is primarily impaired in this model of pressure overload.

• MeSH
• adenylátcyklasy genetika   metabolismus   MeSH
• exprese genu MeSH
• fluoridy farmakologie   MeSH
• hypertrofie levé komory srdeční metabolismus   MeSH
• isoprenalin farmakologie   MeSH
• kardiomegalie genetika   metabolismus   patologie   MeSH
• kardiotonika farmakologie   MeSH
• kolforsin farmakologie   MeSH
• krysa rodu Rattus MeSH
• mangan farmakologie   MeSH
• myokard metabolismus   MeSH
• novorozená zvířata * MeSH
• potkani Wistar MeSH
• protein - isoformy genetika   metabolismus   MeSH
• proteiny vázající GTP metabolismus   MeSH
• signální transdukce MeSH
• stárnutí MeSH
• tlak * MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• adenylátcyklasy MeSH
• fluoridy MeSH
• isoprenalin MeSH
• kardiotonika MeSH
• kolforsin MeSH
• mangan MeSH
• protein - isoformy MeSH
• proteiny vázající GTP MeSH