抄録 地球環境の温暖化によって,野生動物の繁殖や冬眠行動が大きな影響を受けることは容易に想像できる。しかし,実際に冬眠がどのような環境条件に影響されているのかは不明である。そこで,本研究では,冬眠行動を誘発する環境条件について検討を行った。冬眠する齧歯目として知られているシリアンハムスターをモデルとして用いた。冬眠の誘発にとって,気温の低下と日照時間の短縮は最も重要な要因であると考えられる。そこで,ハムスターを恒暗・低温環境下で飼育したところ,冬眠に入った。一方,これらの条件に加えて,飼料としてヒマワリの種子や高脂肪食を充分に与えたのち,給餌制限を行った場合,自由摂食をさせた個体と比較して,短期間で冬眠状態に入ることが見いだされた。このことは,食物の量と組成も冬眠行動の誘発に深く関連することを示唆するものである。また,これまでの実験結果から,体重の大きい個体ほど冬眠に入りやすいことがわかった。このことは,体内に蓄積された脂肪細胞から分泌されるレプチンなどのホルモンが,冬眠行動と関連する可能性を示唆するものである。これらの結果から,冬眠は,環境温度や日照時間,そして食物といった外部環境の変化と関連することが示唆された。 It is considered that global warming and exposure to endocrine disrupting chemicals can influence reproduction and hibernation of wildlife. However, environmental factors responsible for such behavioral differences are not well recognized. Therefore, in this study we analyzed environmental conditions that are critical for inducing hibernation. Non-seasonal hibernators, Syrian hamsters were used in this study. It has been pointed out that a low environmental temperature is an important factor to induce hibernation. So, hamsters were kept at a cold room. After about two or three months, they hibernated. Next, food restriction under the cold environment was performed. When the hamsters were fed sunflower seeds or high fat food not standard laboratory chow and then food supply was restricted, they efficiently hibernated in a shorter time period compared with those which were given free access to food. This suggests that the quantity and nutritional composition of food can affect hibernating behavior in addition to a low environmental temperature. We noticed that hibernation is more efficiently induced in obese hamsters than in thin ones. This may indicate that hormones derived from adipose tissue including leptin could be related to hibernation. These results suggest that hibernation might be associated with external environmental factors (environmental temperature and food composition). arabic 6 English 57
Marwan Draid(3-2007)

Background: The present work was conducted to investigate the effects of lead acetate intoxication on glucose and liver functions in albino rats, and the possible effectiveness of using camel milk to protect against lead induced toxicity. Methods: Eighteen male albino rats were divided into three groups of six, the first was a control group, the second received orally lead acetate in water as (2 ml saline containing 5 mg/kg body weight of lead acetate) and the third received the same lead acetate dose and supplemented with 2 ml of camel milk, the experiment lasted for three weeks. Results: The results indicated that exposure of animals to lead acetate caused a significant increase (p
Marwa M. Draid(6-2016)

The relationship between ATP-induced membrane potential and contraction was inestigated in the smooth muscle of chicken anterior mesenteric artery using micro-electrode and tension recording techniques respectively. Application of ATP to en-dothelium-denuded arterial preparations developed concentration-dependent, slow depolarization which started only at concentrations not less than 10 μM. On the other hand the tension recording experiment revealed that ATP produced concentration dependent contractions, which were evident at concentrations lower than those evoked depolarizing response to ATP (as lower 100 nM). Both depolarizing & contracting responses were abolished by the P2X receptor blocker, PPADS (50 μM) but not by P2Y receptor blocker CBF3GA (100 μM), indicating that the excitatory responses of ATP were mediated via activation of P2X receptor. These findings suggest that ATP-mediated contraction is not dependent on membrane depolarization only, at least at low concentrations in the first order branches of chicken anterior mesenteric artery. arabic 21 English 153
Marwan Draid(7-2012)