利用腎被膜內額外植入同窩動物提供的腦下腺前葉以誘導成慢性血泌乳素過高(Chronic hyperprolactinemia)狀態之Wistar品系雄性大白鼠當作本實驗之動物模式，讓其曝露於低溫束縛壓(Cold-restraint stress)條件下，檢測動物腦內不同核區域之腎上腺素 (Norepinephrine; NE) 含量之變化與胃潰瘍形成之關係乃為本研究之目的。實驗l：移植前 (Day 0) 和移植後第40天(Day 40)由頸靜脈採血，利用放射免疫法測定血清中泌乳素(Prolactin; PRL)濃度，結果實驗組在移植後第40天與對照組相比較，血清泌乳素含量呈現顯著的增加 (P<0.01)。實驗2：移植後第40天之腦下腺前葉移植鼠和偽手術對照鼠，置於低溫(5℃)束縛壓力環境3小時結果發現實驗組之潰瘍指標與對照組比較統計上呈顯著差異 (P<0.05)。實驗3：移植後第40天之腦下腺前葉移植鼠和偽手術對照鼠，置於低溫(5℃) 束縛壓力環境3小時，將動物迅速斷頭犧牲後；腦組織經由冷凍切片微量穿刺取樣(Micropunch)，以高壓液相層析法 (HPLC) 並利用電化學偵測器(EC) 定量腦內不同核區域之NE含量。結果實驗鼠與偽手術移植肌肉片之對照鼠，同在Cold-restraint stress條件下，腦內紋狀體(Corpus striatum)、杏仁體(Amygdaloid body)和下視丘側核(Lateral hypothalamus) 區域之 NE 含量則沒有改變；其中特別是有腦下腺前葉移植之實驗鼠， 曝露於Cold-restraint stress條件下，其腦內前庭耳蝸神經核(Nucleus accumbens; NAc)區域之NE含量與偽手術對照鼠比較時(9.30 ± 13.0 vs 55.5 ± 9.7 ng/mg protein) 統計上呈顯著差異(P<0.05)，此現象顯示該神經元可能已被活化。再者，高血泌乳素狀態之雄鼠組在Cold-restraint stress誘導下產生潰瘍指標比對照組呈有意義的減低(3.40 ± 0.58 mm vs 6.92 ± 1.34 mm)。綜合上述結果得到以下推測，腎被膜接種有腦下腺前葉而有高血泌乳素之雄鼠，曝露於Cold-restraint stress條件下，減緩壓力誘發(Stress-induced)胃潰瘍發生之原因，可能與腦中NAc區域之NE神經元活性增加有關。
The relationship between brain norepinephrine (NE) and development of gastric ulcer induced by Cold-restraint was investigated in male hyperprolactinemic rats. Male Wistar strain rats were divided into two groups: one received extra two pieces of anterior pituitary (AP) from their littermates, the other grafted with several pieces of muscle served as control. Experiment I: On the 40th day after transplantation, the level of serum prolactin (PRL) in the AP-grafted group was higher than those of control (P<0.01). Experiment II: On the 40th day after transplantation, AP-grafted and control rats were restrainted and placed supine in a ventilated refrigerator with an ambient temperature of 5℃ for 3hrs. Although gastric mucosal ulceration was observed in both groups, the ulcer index (including total number and length of gastric mucosal ulceration) was lower in AP-grafted group than that in control group (P<0.05 and P<0.01, respectively). Experiment III: On 40th day after transplantation, all rats was allowed to expose to cold-restraint stress (5℃, 3hrs). After the end of stress, all animal were immediately sacrificed by decapitation, the brain was dissected with Palkovit's micropunch technique. NE content in the different area of brain such as corpus striatum, amygdaloid body, lateral hypothalamus and nucleus accumbens (NAc) were assayed by HPLC with electro chemical detection. The results showed that concentrations of NE in the corpus striatum, amygdaloid body and lateral hypothalamus area of brain were not statistically different between AP-grafted and control rats. However, the AP-grafted and control rats. exhibited significantly higher NE content in the NAc area when compared with control rats (93.0 ± 13.0 versus 55.5 ± 9.7 ng/mg protein, P<0.05). According to these findings, we suggest that protective effect of chronic high serum PRL on gastric mucosal ulceration induced by cold-restraint is probably mediated via an increase of norepinephrinergic neuron activity of NAc area.
