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P-type calcium channels play a key role in the synaptic transmission between mammalian central neurons since a major part of calcium entering pre-synaptic terminals is delivered via these channels. Using conventional whole-cell patch clamp techniques we have studied the effect of μ-opioids on P-type calcium channels in acutely isolated Purkinje neurons from rat cerebellum. The selective μ-opioid agonist DAMGO (10 nM) produced a small, but consistent facilitation of current through P-type calcium channels (10±1%, n=27, p<0.001). The effect of DAMGO was rapid (less than 10 sec) and fully reversible. This effect was both concentration and voltagedependent. The EC 50 for the effect of DAMGO was 1.3±0.4 nM and the saturating concentration was 100 nM. The endogenous selective agonist of μ-opioid receptors, endomorphin-1 demonstrated similar action. Intracellular perfusion of Purkinje neurons with GTPγS (0.5 mM) or GDPβS (0.5 mM), as well as strong depolarizing pre-pulses (+50 mV), did not eliminate facilitatory action of DAMGO on P-channels indicating that this effect is not mediated by Gproteins. Furthermore, the effect of DAMGO was preserved in the presence of a non-specific inhibitor of PKA and PKC, (H7, 10 μM) inside the cell. DAMGO-induced facilitation of Pcurrent was almost completely abolished by the selective μ-opioid antagonist CTOP (100 nM). These observations indicate that μ-type opioid receptors modulate P-type calcium channels in Purkinje neurons via G-protein-independent mechanism.

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Resilience aspects of remote electroencephalography sampling are considered. The possibility to use motion sensors data and measurement of industrial power network interference for detection of failed sampling channels is demonstrated. No significant correlation between signals of failed channels and motion sensors data is shown. Level of 50 Hz spectral component from failed channels significantly differs from level of 50 Hz component of normally operating channel. Conclusions about application of these results for increasing resilience of electroencephalography sampling is made.

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