Ganglion-Specific Splicing of TRPV1 Underlies Infrared Sensation in Vampire Bats

Abstract

laser heating to time-resolve the activation and deactivation of TRPM8. Our data reveal that temperature mainly drives the deactivation rate of the channel, which has Q10~10, while the activation rate has typical temperature dependence (Q10~2-3). That is, cooling mainly increases the open probability of the channel by slowing down channel closing. Thus the cold-sensitive channels work in an opposite way to the heat-sensitive channels in which temperature drives the opening rate while the closing rate is insensitive to temperature. But similar to heat activation of TRPV1, the temperature dependence of cold activation of TRPM8 is also strongly dependent on membrane potentials. At hyperpolarization (À60 mV) the deactivation involves an enthalpy change of~40 kcal/mol, while at depolarization (þ60 mV) the enthalpy is decreased to~20 kcal/mol. The reduction of enthalpy reaches~20 kcal/mol, which far exceeds the electrical energy due to charge movement (<2 kcal/mol for z~0.8), suggesting that the mechanisms of voltage-and temperature-sensing of the channel are coupled. 119-PlatPhosphatidylinositol 4,5-Bisphosphate (PIP2) Controls Magnesium Gatekeeper TRPM6 Activity

Questions, ideas and tools: lessons from bat echolocation

“…Gracheva et al (2011) demonstrated that modified nociceptors (TRPV1, Transient Receptor Potential Vanilloid 1) on the edge of the noseleaf in vampire bats are heat detectors. In other mammals, TRPV1 detect noxious temperatures (>43 C), and in vampire bats, the temperature threshold for activity is reduced.…”

Evolutionary adaptation to thermosensation

“…Accordingly, in heterologous systems, mouse and rat TRPV1 is activated at the same temperature range. In contrast, a zebrafish TRPV1 orthologue, which is essential for noxious heat avoidance in this species, is activated at 328C in the same conditions [22,23].…”

“…Notably, TRPV1-S is specific to trigeminal neurons, which innervate the head, including the three leaf pits. The long TRPV1-L isoform, on the other hand, is expressed in dorsal root ganglia, which innervate different parts of the body [23]. These observations suggest that the TRPV1-S isoform is part of a molecular mechanism that mediates low-intensity heat detection by the leaf pit organ.…”

“…This structural alteration could be a cause for the shift in the apparent temperature activation threshold of zebrafish TRPV1 [23]. Indeed, a similar truncation of a mammalian TRPV1 shifts detectable channel activation from 428C to $308C [24].…”

“…Perhaps it is a good idea to start exploiting the magnificent diversity of living organisms which have been continuously shaped and changed in evolution for over hundreds millions of years. Indeed, studies from non-standard species such as snakes and bats have yielded much unexpected insights into physiology of thermal reception [9,23]. The unique physiological attributes of hibernating mammals, such as their ability to drop core body temperature and remain comfortably cold for a long period of time at temperatures that are unbearable for most other mammals, warrant immediate attention from researchers interested in studying thermosensation, thermoregulation and thermogenesis [50 ].…”