Specification 

  Definition 

The paws of mice and rats are very sensitive to heat at temperatures which are not damaging the skin. The responses are jumping, withdrawal of the paws and licking of the paws. The time until these responses occur is prolonged after administration of centrally acting analgesics, whereas peripheral analgesics of the acetylsalicylic acid or phenyl-acetic acid type do not generally affect these responses.

The hot plate consists of a electrically heated surface. The temperature is controlled for 55° to 56 °C.

The animals are placed on the hot plate and the time until either licking or jumping occurs is recorded by a built-in stop-watch. The latency is recorded before and after 20, 60 and 90 min following oral or subcutaneous administration of the standard or the test compound. The prolongation of the latency times comparing the values before and after administration of the test compounds or the values of the control with the experimental groups can be used for statistical comparison using the t-test. Alternatively, the values which exceed the value before administration for 50% or 100% can be regarded as positive and ED50 values can be calculated. Doses of 8 mg/kg s.c. morphine hydrochloride and 30 mg/kg s.c. codeine hydrochloride were found to be effective, whereas aspirin showed no effect even at high doses.

The hot plate test has been used by many investigators and has been found to be suitable for evaluation of centrally but not of peripherally acting analgesics. Mice as well as rats have been used. The method has the drawback that sedatives and muscle relaxants or psychotomimetics cause false positives, while mixed opiate agonists-antagonists provide unreliable results. The validity of the test has been shown even in the presence of substantial impairment of motor performance.

Date of hot-plate test are often expressed as percent maximum possible effect (%MPE).

%MPE=(test-baseline)/(cut off- baseline)X100

Where test is the latency to response after treatment; baseline is the latency to response prior to treatment; and cut off is the preset time at which the test will be ended in the absence of a response.

citation

Ellagic acid improves hyperalgesia and cognitive deficiency in 6-hydroxidopamine induced rat model of Parkinson’s disease .(Mojtaba Dolatshahi 1, 2, Yaghoob Farbood 1, 2*, Alireza Sarkaki 1, 2, Seyed Mohammad Taqhi Mansouri 1, 3, Ali Khodadadi)

Antinociceptive effect of clavulanic acid and its preventive activity against development of morphine tolerance and dependence in animal models.(V. Hajhashemi* and Kh. Dehdashti )

Antinociceptive Effect of the Endemic Species Glaucium vitellinum Boiss and Buhse.(Elahe Rangriz,1 Zahra Mousavi,1,* Parvaneh Najafizadeh,2 and Jinous Asgarpanah)

 Antinociceptive Effect of the Endemic Species Glaucium vitellinum Boiss and Buhse.(Elahe Rangriz,1 Zahra Mousavi,1,* Parvaneh Najafizadeh,2 and Jinous Asgarpanah)

Ellagic acid improves hyperalgesia and cognitive deficiency in 6-hydroxidopamine induced rat model of Parkinson’s disease.(Mojtaba Dolatshahi 1, 2, Yaghoob Farbood 1, 2*, Alireza Sarkaki 1, 2, Seyed Mohammad Taqhi Mansouri 1, 3, Ali Khodadadi)

تو ضیحات فارسی

Hot plate به طور گسترده ای برای بررسی اثرات داروهای analgesic برروی حساسیت درد ناشی از گرما (thermal pain sensitivity ) و یا بررسی thermal pain Reflex در حیوانات کوچک آزمایشی، مورد استفاده قرار می گیرد.از انجایی که پنجه های Rat و mice به تغییرات دمایی بسیار حساس می باشد، با افزایش دما، حیوان پاسخ هایی مثل پریدن، عقب کشیدن اندام و یا لیسیدن از خود نشان می دهد.استفاده از برخی داروها مثل ضددردهای مرکزی موجب به تعویق افتادن پاسخ های فوق می شود در حالیکه استفاده از ضد دردهای محیطی مثل acetylsalicylic acid و یا phenyl-acetic acid روی پاسخ های فوق اثر چندانی ندارند.

در این تست حیوان روی هات پلیت قرار می گیرد، مدت زمانی که طول می کشد تا حیوان پاسخی مثل پریدن،لیسیدن و یا عقب کشیدن اندام نشان دهد به عنوان latency time در نظر گرفته می شود و توسط تایمر دستگاه ثبت می گردد.latency time قبل از استفاده از دارو و 20،60،90 دقیقه پس از استفاده از دارو اندازه گیری می شود.