溫度梯度測試儀 TGR

The Thermal Gradient Ring is a novel device, which allows recording and analysis of Comprehensive Thermal Preference Phenotyping in Mice, according to Zimmermann's method. 

In recent years the cellular and molecular mechanisms of temperature sensing and thermoregulation are subject of intensive research. Some researchers have evidenced the limits of the existing tests: to overcome current limitations we have designed a novel circular thermal gradient assay, for thermal preference phenotyping, based on the paper "Comprehensive thermal Preference Phenotyping in Mice using a Novel Automated Circular Gradient Assay", published by University Erlangen-Nuernberg (see Zimmmermann's paper). The new TGR (Thermal Gradient Ring) provides a high degree of freedom, i.e. thermal choice, and eliminates experimenter bias

The TGR is suitable to test neuropathic pain, and allows discerning exploratory behavior from thermal selection behavior!

The advantages brought about by the circular design are duplicate values, no border effects and no spatial cues, guaranteeing bias-free, reproducible data. The TGR is more sensitive than previous methods: gradient setup is superior to two plate choice design (reflects a more complex physiological environment, requires less time, less manpower and less mice).

The TGR consists of a circular running track, which provides a thermal gradient between the two extremes of a cold and a hot zone (respectively 15° and 40°C in Zimmermann's paper) in which the mouse is free to move. The Thermal Insulated Ring-shaped Aluminium Runway has an ID of 45cm and 57cm OD.

A heating and a heating/cooling device (both based on the well tested technology employed in Ugo Basile Hot/Cold Plate), positioned on the opposite sides of the ring, create a symmetric thermal gradient, controlled by 4 embedded thermocouples measuring the exact temperature gradient in real time.

Each side of the ring is divided into 12 zones, in which the temperature Δ is proportionally divided: for example, in the protocol described in the method paper, where the two preset temperatures are respectively 15°C and 40°C, each sector represents an increment of 2.27°C.

Recording and analysis of thermal preference behavior is accomplished by Ethovision, via the USB camera which is part of the set-up. Data output include:

• Preference Temperature time course ± SD
• Time lag to cover zones above a defined temperature (time course)
• Zone histogram 

The set-up includes a dedicated support, which holds a BW USB camera, and a set of 4 dual lights (visible and I.R.). The software is to be purchased separately

"Currently available behavioral assays to quantify normal cold sensitivity, cold hypersensitivity and cold hyperalgesia in mice have betimes created conflicting results in the literature. Some only capture a limited spectrum of thermal experiences, others are prone to experimenter bias or are not sensitive enough to detect the contribution of ion channels to cold sensing because in mice smaller alterations in cold nociception do not manifest as frank behavioral changes. To overcome current limitations we have designed a novel device that is automated, provides a high degree of freedom, i.e. thermal choice, and eliminates experimenter bias. The device represents a thermal gradient assay designed as a circular running track. It allows discerning exploratory behavior from thermal selection behavior and provides increased accuracy by providing measured values in duplicate and by removing edge artifacts. Our custom-designed automated offline analysis by a blob detection algorithm is devoid of movement artifacts, removes light reflection artifacts and provides an internal quality control parameter which we validated. The assay delivers discrete information on a large range of parameters extracted from the occupancy of thermally defined zones such as preference temperature and skew of the distribution. We demonstrate that the assay allows increasingly accurate phenotyping of thermal sensitivity in transgenic mice by disclosing yet unrecognized details on the phenotypes of TRPM8-, TRPA1- and TRPM8/A1-deficient mice."

from "Comprehensive thermal preference phenotyping in mice using a novel automated circular gradient assay"

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