With the suggestion that while high oxygen levels may alter the response beyond the receptor, with wrong information about excitation-contraction coupling; it was observed that levels of oxygen affect both the calcium channel blockers and facilitators with net reduction of influx or utilisation of external calcium. In this our study, using rat tail artery activated by noradernaline and potassium chloride in the presence of Bay K. 8644 and nifedipine at different oxygen levels, we showed that desensitisation of the responses of the vascular smooth muscle occurred.
With the suggestion that while high oxygen levels may alter the response beyond the receptor, with wrong information about excitation-contraction coupling; it was observed that levels of oxygen affect both the calcium channel blockers and facilitators with net reduction of influx or utilisation of external calcium. In this our study, using rat tail artery activated by noradernaline and potassium chloride in the presence of Bay K. 8644 and nifedipine at different oxygen levels, we showed that desensitisation of the responses of the vascular smooth muscle occurred.
Smooth muscle tone and sensitivity in several vascular beds are known to change with temperature. While there is considerable evidence for radical changes in vascular smooth muscle responses to temperature changes, the
influence of desensitization and sensitivity to calcium and Bay K 8644 or nifedipine under these conditions are unknown and this study aimed at investigating these in rat tail artery, rabbit ear artery and cat paw artery.
It has been shown that desensitization of the responses of vascular smooth muscle could occur if the physiological saline composition is altered. The extent to which Bay K 8644 and nifedipine affect the calcium responses of a vascular
smooth muscle and their effects on desensitized tissue responses are yet to be quantified and this is what this study aims at doing on calcium-mediated responses in the rat tail artery and on the desensitization of the responses of the
The modulatory effects of different levels of oxygen in altering the responses of smooth muscles to different activating agents or net influx/utilization of external calcium have been extensively studied by various groups of workers. In all these investigations, it is generally agreed that reduction of the...
Desensitisation and the effects of Bay K 8644 and nifedipine on the calciumsensitivity of smooth muscle contraction were studied in the isolated perfused rat tail artery, employing the activators noradrenaline (NA) (3μM) and potassium
chloride (KCI) (100mM). Experiments were conducted in Ca2+ - buffered saline. Activators were added when [Ca2+]free was low (1μM) and then [Ca2+]free was increased stepwise to give a Ca2+ concentration/response curve (CRC).
