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When ambient temperature is decreased in mammals, autonomic and behavioral heat-gain responses occur to maintain their core temperatures. However, what molecules in cutaneous sensory nerve endings mediate cooling-induced responses is unclear. Recently, transient receptor potential melastatin-8 (TRPM8) has been identified in cell bodies of sensory neurons as low-temperature and menthol-activated cation channel. We hypothesized that TRPM8 mediates cooling-induced autonomic and behavioral heat-gain responses. To activate TRPM8 specifically, we applied 1-10% menthol to the skin of whole trunk in mice instead of cooling and measured core temperatures and autonomic and behavioral heat-gain responses. Solvent of menthol (100% ethanol) was used as control. Significant elevation of core temperatures was observed between 20 and 120 min after menthol application. Pretreatment with diclofenac sodium, an antipyretic drug, did not affect this hyperthermia, indicating that the menthol-induced hyperthermia is not fever. Menthol application induced a rise in oxygen consumption, shivering-like muscle activity, tail skin vasoconstriction (autonomic responses), and heat-seeking behavior. All of them are typical heat-gain responses. These results support the hypothesis that TRPM8 mediates cooling-induced autonomic and behavioral heat-gain responses. thermoregulation; transient receptor potential channel(s); metabolism

The results of an experimental study on the negative corona current pulse (NCCP) wave forms are presented. The experiments were restricted to the first NCCPs and expanded on earlier work to higher gas pressures and larger radii of the cathode curvature. It is indicated that the ionization mechanism regulating the pulse formation is a feed-forward-to-gas streamer mechanism, and the Alexandrov and Morrow cathode photoemission-fed multiple avalanche ionization mechanism only played a leading role in the discharge current rise to the pulse leading edge.

Tissue slices of rat nucleus of the solitary tract (NTS) were analyzed by whole cell patch-clamp techniques to determine the presence and kinetics of nicotinic acetylcholine receptor (nAChR)-mediated signal transduction. Whole cell patch-clamp analysis of whole cell currents in rat medullary NTS slices indicated the presence of nAChRs that possessed similar properties to neuronal nAChR. Furthermore, nAChR-mediated signal transduction from afferent nerves to neurons in the NTS involved the diffusion of acetylcholine.

Optimum acceptance angle of a compound parabolic concentrator (CPC) is studied by the use of an insolation model proposed in this paper. The insolation consists of two components; diffuse and direct. The direct radiation is supposed to be distributed in the field within [+ or -]23.5 [degrees] of declination on the celestial hemisphere and the diffuse radiation is assumed to have uniform irradiance. This yearly insolation model suggests that the optimum half-acceptance angle at the two-dimensional CPC becomes 26 [degrees] irrespective of the change of the diffuse radiation fraction. This result leads us to the conclusion that, almost all over the world, a common CPC could be used as an optimum concentration for many solar radiation collecting systems.

A new design method for a compound parabolic concentrator heat collector is described. The conventional design of the ideal compound parabolic concentrator collector has a touching point between a light absorber and the reflectors. This structure is not preferable from the standpoint of conductive heat leakage and thermal stress on reflector materials. On the other hand, if the absorber and the reflectors are separated from each other, the gap between them usually causes optical errors such as light transmission loss or an increase in the reflection number. We discuss the fact that ideal heat collection is possible, in spite of the gap, by introducing the idea of an effective heat concentration ratio.