| Popis: |
The effect of 0.03-1.0 μM noradrenaline on the neurogenic contractile response to electrical field stimulation of the juvenile rat tail artery segment in control conditions and after the solution pH decrease from 7.4 to 6.6 was studied. Acidosis were shown to inhibit this response significantly at all frequencies of stimulation used (3, 5, 10, and 40 Hz). Noradrenaline potentiated neurogenic vasoconstriction diminished spontaneously or by low pH. The potentiative effect of noradrenaline in acidic solution was more pronounced at higher frequencies of stimulation and noradrenaline concentrations. This phenomenon can, at least in part, account for blood flow redistribution from less important organs to vital ones during exercise which is characterized by acidosis, augmented sympathetic nerve activity and increased levels of noradrenaline. |
