Objective: To investigate the expression of three acid-sensing ion channel (ASIC) subtypes termed as ASIC1b, ASIC2a, and ASIC3 in the neurons of trapezoid body and lateral paragigantocellular nucleus of rat brainstem, and the effects of intermittent hypoxia on their expression.
Methods: The intermittent hypoxic rat model was established, of which the blood gas analysis was tested after 12 days. The immunohistochemistry SABC method was performed to test the expression of ASIC1b, ASIC2a, and ASIC3 in neurons of trapezoid body and lateral paragigantocellular nucleus in the control (O2) and intermittent hypoxic (IH) groups of rats.
Results: The ASIC1b-, ASIC2a- and ASIC3-positive immunoreactive neurons all could be observed in the nucleus of trapezoid body and lateral paragigantocellular nucleus. The intermittent hypoxia group, the numerical density of ASIC1b-positive immunoreactive neurons (cell/mm3) decreased in the nucleus of trapezoid body (P<0.05), but did not significantly change in the lateral paragigantocellular nucleus (P>0.05), the grey level did not significantly change in both the nucleus of trapezoid body and lateral paragigantocellular nucleus (P>0.05); the numerical density of ASIC2a-positive immunoreactive neurons (cell/mm3) did not significantly change in the nucleus of trapezoid body and lateral paragigantocellular nucleus (P>0.05), the grey level in the nucleus of trapezoid body increased (P<0.05) while it did not significantly change in the lateral paragigantocellular nucleus (P>0.05); the numerical density of ASIC3-positive immunoreactive neurons (cell/mm3) decreased in the lateral paragigantocellular nucleus (P<0.05), but it did not significantly change in the nucleus of trapezoid body (P>0.05), the grey level did not significantly change in the nucleus of trapezoid body and lateral paragigantocellular nucleus (P>0.05).
Conclusion: The ASIC1b, ASIC2a, and ASIC3 exist in the neurons of trapezoid body and lateral paragigantocellular nucleus in the rat brainstem under normal condition, and their expressions in the two nuclei are different to intermittent hypoxia, which means that the roles of subtype of ASICs in different area may be different in the respiratory effects induced by hypoxia.