In addition to cyanide, other factors in cigarette smoke must affect OPR. Unlike inhibition of OPR by cyanide, which is reversible, inhibition of OPR by smoke solutions is irreversible, and OPR continues to decrease after washout of smoke solutions. The factor(s) involved in irreversible inhibition of OPR has not yet been identified but appears to decrease adhesion between the OCC and cilia. In the absence of adhesion, even cilia that are beating normally are not able to pick up an OCC. In the current study, we did not observe any effect of KCN on adhesion of the OCC to the cilia. Thus the reduction of OPR by cyanide was, at least in part, due to inhibition of CBF. Buy Asthma Inhalers Online
It is possible that other ciliary parameters, such as amplitude and metachrony, were also affected by cyanide. Evidence for this suggestion comes from comparing the sensitivity of OPR and CBF to cyanide. CBF and OPR were inhibited by KCN concentrations of 50 (xM and 15 jxM, respectively. Thus OPR was about 3.3 times more sensitive to cyanide than CBF. This difference in the sensitivity of CBF and OPR to cyanide could be explained if cyanide were also affecting other parameters such as the amplitude or metachrony of the ciliary beat. A decrease in either of these parameters would likewise decrease OPR and could directly account for inhibition of OPR at cyanide concentrations below those that inhibit CBF.