In impulse recordings from hypothalamic neurons in rat brain slices sensitization phenomena had been observed when ethanol (EtOH) was applied during slow sinusoidal temperature changes. EtOH application (0.1–0.4%) lead to a drastically enhanced temperature sensitivity, which, remarkably, mainly resulted from stronger inhibition during cooling while the firing rate (FR) during warming was only slightly enhanced. To simulate these EtOH induced sensitization in a simplified Hodgkin-Huxley type model (1.) we have added a temperature sensitive current and (2.) we have assumed that its activation curve is modified by EtOH. With appropriate adjustment of the temperature dependent activation curve it turned out that an EtOH induced steepening of the curve is sufficient to account for the experimentally observed sensitization phenomena very well. Remarkably, although the temperature varies symmetrically around 37°C (±2°C) with, accordingly, symmetrical changes of the temperature dependent current, the changes of the FR during cooling are much stronger than during warming. More detailed insights are expected from a combination of modeling studies with patch clamp-experiments.

This work was supported by the European Union through the Network of Excellence BioSim, Contract No. LSHB-CT-2004005137.