Primary somatosensory cortex in rats with pain-related behaviours due to a peripheral mononeuropathy after moderate ligation of one sciatic nerve: neuronal responsivity to somatic stimulation

Summary Single-unit recordings were made under moderate gaseous anaesthesia in the hindpaw representation area of the two primary somatosensory motor cortices (SmI) of rats (n = 58) rendered mononeuropathic by four loose ligatures placed around one common sciatic nerve 2–3 weeks beforehand. The rats exhibited clear hyperalgesia and allodynia from the paw with the ligated sciatic nerve, to both mechanical and thermal stimuli. From the tested neuronal population (n = 640), about the same proportion could be activated by somatic stimuli in each cortex: 165/362 (45%) in the cortex contralateral to the ligated sciatic nerve (Cc), 105/278 (37%) in the cortex ipsilateral to the ligated sciatic nerve (Ci). Neurones driven by light touch, exhibited RFs strictly contralateral to the recording sites. Their proportion and response characteristics were similar regardless of recording side. However, the number of neurones with RFs in the sciatic nerve territory was above 95% in the Ci, and was dramatically reduced to 43 % in the Cc. By contrast, the number of neurones with RFs supplied by the saphenous nerve reached 57% on this side. Although the RF size of all the neurones appeared roughly normal, there were fewer Cc than Ci neurones with RFs located on the paw itself and with RFs of extremely small size in the sciatic nerve territory. The proportion of neurones responding to a joint stimulus was significantly higher in the Cc than in the Ci. The neuronal responses to joint stimuli of the paw with the ligated sciatic nerve were significantly more sustained than those recorded in the Ci and elicited from the normal paw. The proportion of neurones driven by mechanical stimulation which gave rise to nociceptive reactions in freely moving animals, i.e. nociceptive neurones, was comparable in each cortex. However, half of the Cc neurones exhibited paroxysmal discharges occuring without intentional stimulation and of long duration (l min to several minutes). Only 66% of Cc but 93% of Ci nociceptive neurones were exclusively activated by pinch. The remaining Cc neurones were also activated by applying moderate pressure to the paw with the ligated nerve. Pinch responses from the paw with the ligated nerve were often more intense and of longer duration than responses elicited from the intact paw. The nociceptive Cc neurones were especially sensitive to thermal stimuli of 39–44° C when the stimuli were applied to the paw with the ligated nerve. They also responded vigorously to a 10° C stimulus applied to this paw. They were therefore, sensitive to thermal stimuli usually considered to be in the non-noxious range. In the SmI cortex opposite to the ligated sciatic nerve, there was no change in the proportion of somatosensory neurones, but a rearrangement of the various somatic inputs. Although reduced, there were consistent light tactile inputs from the damaged sciatic nerve giving rise to roughly normal neuronal responses, and simultaneously a noticeable increase in tactile signals from the saphenous nerve territory. There was also a significant increase in joint inputs from the paw with the ligated sciatic nerve. The possible functional role of such input rearrangement is discussed. The dramatic changes in the responses of nociceptive neurones to stimuli applied to the paw with the ligated sciatic nerve and the clear decrease in their activation threshold to mechanical and thermal stimuli could account for some of the abnormal pain-related behaviours that were exhibited. These data emphasize, again, that the primary sensory cortex is involved in nociceptive processing.     

Ⅱ型糖尿病患者的神经传导速度变化

目的：探讨Ⅱ型糖尿病患者神经传导速度（NCV）改变与其影响因素之间的关系。方法：测定164例Ⅱ型糖尿,病患者NCV,将病人分为NCV阳性组与NCV阴性组进行分析。结果：NCV阳性组和NCV阴性组之间年龄和病程存在显著差异（P＜0．01和P＜0．001）,两组间血脂,血糖水平无明显差异,在NCV阳性组中,SCV无益 一低于正常,MCV 值在正常范围内,SCV和MCV间有显著差异,病程虎长,NCV的变化越明显,各条神经NCV之间存在显著相关性,结论：在II型糖尿病病人中,周围神经传导速度变化及其程度与病程显著相关,与年龄有一定相关性,而与血糖,血脂水平无相关性;感觉神经与运动神经的受损程度之间均密切相关,患病5年以上者更警惕神经病变的发生。     

正常国人正中神经、尺神经、腓神经及腓肠神经刺激阈值的检测研究

目的：研究正常健康国人双侧正中神经、尺神经、腓神经及腓肠神经等四大周围神经刺激阈值正常值,为应用神经阈值诊断周围神经病变提供合理的数据。方法：健康志愿者20名中,男12名,女8名,分别检测双侧正中神经、尺神经、腓神经远端运动神经刺激阈值和腓肠感觉神经刺激阈值,对结果进行统计学分析。结果：上肢双侧正中神经、尺神经运动神经刺激阈值明显低于下肢腓神经运动神经刺激阈值。所测双侧正中神经、尺神经、腓神经和腓肠神经刺激阈值：左右两侧间差异无统计学意义,P值分别为0．39、0．11、0．07和0．51;男女性别间差异无统计学意义,P值分别为0．90、0．80、0．93、0．22、0．57、0．27、0．34和0．71;不同身高组间左右侧的差异也无统计学意义,P值分别为0．49、0．27、0．66、0．61、0．49、0．34、0．18、0．20。结论：上肢运动神经刺激阈值低于下肢,个体同名神经阈值左右侧间、不同性别者间、不同身高者间差异比较均无统计学意义;正常国人神经刺激阈值正常值范围可为周围神经病变的诊断提供参考依据。     

2型糖尿病患者的肺弥散功能检测分析(英)

目的：检测2型糖尿病患者的肺通气和弥散功能，探讨肺脏是否为糖尿病慢性病变的靶器官。方法： 对107名2型糖尿病患者行肺通气及弥散功能检测，并与61名年龄、性别匹配的健康者比较。糖尿病患者需行糖化血红蛋白（HbA1c）、尿白蛋白排泄率（AER）检测、眼底检查以及神经传导速度检查，以评价血糖控制水平以及糖尿病微血管病变状况。结果： 2型糖尿病组肺通气功能与正常对照组相比，无显著差异。2型糖尿病组一氧化碳弥散量（DLCO）及单位肺泡容积的一氧化碳弥散量（DLCO/VA）较对照组明显降低（P<0.05）。DLCO、DLCO/VA与微血管病变积分呈负相关（r分别为-0.291、 -0.324，P<0.01）。此外，DLCO/VA还与年龄、病程呈负相关（r分别为-0.269、-0.236，P<0.05）。结论： 2型糖尿病患者虽然肺通气功能基本正常，但有弥散功能受损，提示肺脏可能也是糖尿病慢性病变的靶器官之一。     

丝胶对2型糖尿病大鼠睾丸生长激素/胰岛素样生长因子-1轴的作用

目的 探讨丝胶对2型糖尿病大鼠睾丸生长激素（GH）/胰岛素样生长因子-1（IGF-1）轴的作用。 方法 40只雄性SD大鼠随机分为正常对照组、糖尿病模型组、丝胶治疗组和阳性对照组,每组均为10只。链脲佐菌素连续腹腔注射制作2型糖尿病大鼠模型,1周后以血糖≥16.7mmol/L作为成模标准。待模型成功建立后,模型组大鼠不做任何处理,丝胶治疗组大鼠给予丝胶灌胃［2.4g/(kg&#8226;d)］,阳性对照组大鼠给予二甲双胍［55.33mg/(kg&#8226;d)］灌胃,均为35d。采用酶联免疫吸附测定（ELISA）方法检测大鼠血清睾酮、GH和IGF-1水平;分别采用免疫组织化学染色、免疫印迹法和RT-PCR法检测睾丸GH、GH受体（GHR）和IGF-1的表达。 结果 丝胶可明显降低糖尿病大鼠血GH水平、下调睾丸GH的表达,升高血IGF-1和睾酮水平,上调睾丸IGF-1和GHR的表达（P＜0.05,P＜0.01）。并且丝胶治疗组各项指标与阳性对照组比较无明显差别（P＞0.05）。 结论 丝胶可通过调节糖尿病时GH/IGF-1轴紊乱改善生精功能,发挥对糖尿病生殖功能损害的保护作用,其作用与二甲双胍相当。     

Peripheral neuropathy in patients with diabetes mellitus presenting as Bell's palsy

The aim of this study is to evaluate the peripheral nerves in diabetes mellitus with or without peripheral facial paralysis (PFP). A total of 49 diabetic patients with PFP within the last year (23 females, mean age 60.3 +/- 9.3), and 83 diabetic patients without PFP (41 females, mean age 59.5 +/- 9.9) were enrolled. The neurological examination, eye-blinking response, needle EMG and electrophysiological parameters of peripheral nerves were evaluated. The neuropathic pain, other positive and negative sensory symptoms were statistically more frequent in controls than the PFP group, while no difference was noted in total neuropathy score. Sural sensorial nerve action potential amplitudes were same in both groups, but median nerve amplitudes were significantly lower in the PFP group. It is suggested that PFP is not a part of multifocal neuropathy in diabetes mellitus. However, at least some parts of the nerve conduction studies were involved, focal neuropathies were more frequent while sensory neuropathies with small nerve fiber involvement were less frequent in diabetes patients with PFP.     

Effectiveness of mobile and internet intervention in patients with obese type 2 diabetes

PURPOSE: The present study evaluated whether an intervention using the SMS by personal cellular phone and internet would improve the levels of plasma glucose of obese type 2 diabetes at 3, 6, 9, and 12 months. METHODS: This is a quasi-experimental design with pre- and follow-up tests. Participants were recruited from the endocrinology outpatient department of tertiary care hospital located in an urban city of South Korea. Eighteen patients were randomly assigned to an intervention group and 16 to a control group. The goal of the intervention was to decrease body weight and keep blood glucose concentrations close to the normal range. Patients were requested to record their blood glucose level in a weekly diary on the website by personal cellular phones or computer internet. The researcher sent optimal recommendations to each patient, by both the cellular phone and the Internet weekly. The intervention was applied for 1 year. RESULTS: Glycosylated hemoglobin (HbA(1)c) decreased 1.22 percentage points at 3 months, 1.09 percentage points at 6 months, 1.47 percentage points at 9 months, and 1.49 percentage points at 12 months compared with baseline in the intervention group (all time points, p<0.05). The percentage change in the control group was, however, not significant. Patients in the intervention group had a decrease of 2-h post-prandial test (2HPPT) of 120.1mg/dl at 3 months, 58.9 mg/dl at 6 months, 62.0mg/dl at 9 months, and 102.9 mg/dl at 12 months compared with baseline (all time points, p<0.05). The mean change in the control group was, however, not significant. CONCLUSION: This web-based intervention using SMS of personal cellular phone and Internet improved HbA(1)c and 2HPPT at 3, 6, 9, and 12 months in patients with obese type 2 diabetes.     

实验性糖尿病骨质疏松的扫描电镜观察

目的;研究糖尿病性骨质疏松的骨结构改变。方法：用四氧嘧啶注入W ister大鼠尾静脉的方法,制成糖尿病动物模型。分别取成模后4和6个月的大鼠胫骨,在扫描电镜下观察骨结构的改变。结果：糖尿病大鼠的胫骨的骨密质变薄,表面有峰窝状的骨质吸收。骨小梁数量明显减少,骨质松脆、断裂,骨髓腔扩大。结论：糖尿病可引起骨的三维结构破坏和骨质疏松,随之造成骨的强度下降及骨折。     

2型糖尿病鼠脑梗死模型的建立及相关指标分析

目的：在具有胰岛素抵抗特征近似人类2型糖尿病（T2DM）的大鼠身上建立脑梗死模型。方法：SD雄性大鼠120只,其中90只用高脂高糖和链脲佐菌素（STZ）制成T2DM模型,另30只为对照组。对照组和T2DM成模大鼠随机分为假手术组（A1组、B1组）和手术组（A2组、B2组）。采用神经功能缺损量表（NSS）评分、TTC染色与HE染色观察神经功能缺损征、脑梗死体积及病理改变。结果：T2DM成模率为72％,血脂指标与对照组相比差异有统计学意义（P〈0．01）,且血脂异常表现与临床T2DM患者近似。A2组NSS评分3—4级者占75％,脑梗死体积为（55．23±9．59）mm^3,脑梗死成模率为75％;B2组NSS评分3—4级者占60％,脑梗死体积为（54．33±6．39）mm^3,脑梗死成模率为53％。结论：高脂膳食结合STZ注射能复制出接近人类T2DM的动物模型,在此基础上制成的脑梗死模型稳定性和重复性好,是研究人类糖尿病脑梗死病理过程较为理想的动物模型。     

抵抗素（resistin）与2型糖尿病及肥胖症相关研究进展

Resistin, a new hormone found in the year 2001 and secreted by adipocytes, is related to type 2 diabetes and obesity. It brings some hope to solve the medical hamper of insulin resistance. The resistin discovery, molecule structure, function and expression, secretion regulation as well as gene polymorphism are reviewed in the article.     

2型糖尿病合并动脉粥样硬化大鼠模型的建立

目的：制备一种发病过程类似人类普通2型糖尿病合并动脉粥样硬化的大鼠模型。 方法： 取出生 3 d 的Wistar大鼠20窝，随机分正常对照组和造模组两组，造模组按75 mg/kg体重剂量腹腔注射链脲佐菌素(STZ)（临用前用pH 7.4，0.1 mmol/L柠檬酸-柠檬酸钠溶液配制成2%的溶液），正常对照组腹腔注射等体积的柠檬酸-柠檬酸钠溶液，1次性注射，1月后断乳，挑选血糖值在11.1-20 mmol/L雄性大鼠，随机选出20只作为模型对照组，喂以普通饲料，其余作为糖尿病合并动脉粥样硬化造模组喂以高胆固醇高脂高糖饲料，全部动物于喂饲料后第0、2、5个月测体重及尾静脉采用测血糖、血脂、胰岛素，各阶段处死部分动物作病理观察。 结果： 高热量组大鼠体重高于正常组，血糖、血脂、血清胰岛素水平及胰腺和主动脉病理学观察与正常组差异不明显；模型对照组大鼠体重轻于对照组，血糖、血脂、血清胰岛素水平也与对照组有明显差异(P<0.05)；胰腺和主动脉病理学观察与对照组比较有明显改变；模型组大鼠体重明显大于对照组，血糖、血脂、血清胰岛素水平显著增加(P<0.01)；胰腺和主动脉病理学观察有非常显著改变。 结论： 该大鼠模型是研究糖尿病血管并发症的一种理想模型。     

瘦素、抵抗素、2型糖尿病间的相关性研究

目的：研究血浆瘦素与抵抗素、体重指数、腰围、腰臀比、血脂、胰岛素敏感性指数等的关系。方法：对43例新诊断2型糖尿病患者及37例糖耐量正常者，测定空腹血浆瘦素、胰岛素、血糖、血脂及抵抗素浓度。结果：相关分析显示性别、体重指数（BMI）、腰围、腰臀比、胰岛素与瘦素呈显著正相关（r分别为0.623,0.534，0.516，0.302，0.354，均P<0.01），IAI与瘦素呈显著负相关(r=-0.373,P<0.01),甘油三酯、胆固醇空腹血糖与瘦素无明显相关。瘦素与抵抗素无相关性（r=0.101,P>0.05）结论：空腹血浆瘦素水平与肥胖程度、胰岛素抵抗呈显著正相关，与抵抗素无关。瘦素可能与2型糖尿病的发病有关。     

肥胖2型糖尿病患者血清E-选择素水平与氧化应激的关系

目的： 探讨肥胖2型糖尿病（DM）患者血清E-选择素及氧化应激变化的关系。 方法： 检测肥胖2型DM患者血清E-选择素、氧化低密度脂蛋白胆固醇（ox-LDL）、血清丙二醛(MDA)含量和血清超氧化物歧化酶（SOD）活性。 结果： 非肥胖和肥胖2型DM患者E-选择素、ox-LDL和MDA含量均显著高于正常对照组（P<0.05），HDL-C、HDL2-C和HDL3-C含量均显著低于正常对照组（P<0.01），肥胖2型DM患者SOD活性显著低于正常对照组（P<0.01）。肥胖2型DM患者的E-选择素和MDA含量均明显高于非肥胖2型DM患者（P<0.05）,而SOD活性明显低于2型DM患者（P<0.01）。肥胖2型DM患者E-选择素与HbA1c、腰围、TC、ox-LDL和MDA正相关（r=0.352, P<0.05；r=0.634，P<0.05；r=0.517，P<0.05；r=0.480，P<0.05;r=0.572，P<0.05），与HDL3-C呈负相关（r=-0.374，P<0.05）。 结论： 肥胖2型DM患者血清E-选择素含量明显增加，氧化应激可能参与其变化。     

Association of a polymorphism in the betacellulin gene with type 1 diabetes mellitus in two populations

Betacellulin, a member of the epidermal growth factor family, is expressed in fetal and adult pancreas. In vitro and in vivo studies suggest a role for betacellulin in islet neogenesis and regeneration. Therefore, a mutation in the betacellulin gene might lead to fewer beta cells. With reduced beta cell reserve, beta cells may not be able to compensate for an autoimmune attack, and in turn, susceptibility to type 1 diabetes mellitus (T1DM) would increase. Previous mutational analysis identified seven polymorphisms in the betacellulin gene [5′ UT (−233G>C, −226A>G), exon 1 (TGC19GGC, Cys7Gly), exon 2 (CTC130TTC, Leu44Phe), exon 4 (TTG370ATG, Leu124Met), intron 2 (-31T>C), and intron 4 (-4C>T)]. An association study of these variants with T1DM was first carried out in 100 Caucasian subjects with T1DM and 282 Caucasian subjects without diabetes recruited at the University of Maryland. The frequency of the intron 4 T-4 allele was significantly higher among nondiabetic controls than that among diabetic cases (0.29 vs 0.21, p=0.04). Allele frequencies for the other polymorphisms did not differ significantly between cases and controls. The intron 4 T-4 association was then replicated by transmission disequilibrium testing in a separate population of Caucasian parent/offspring with T1DM trios (n=168 trios, 113 informative) recruited at the Medical College of Wisconsin (p=0.024). An interaction of the intron 4 T-4 allele and human leukocyte antigen (HLA) was also detected with undertransmission of the T allele in those T1DM subjects with susceptible HLA types as compared to those T1DM subjects without susceptible HLA types (p=0.018). RNA studies of the intron T-4 variant showed similar RNA levels for intron 4 T-4 and intron 4 C-4 alleles. Additionally, there was no evidence for an effect of this variant on exon–intron splicing. We conclude that the intron 4 T-4 allele in the betacellulin gene is associated with lower risk of T1DM and may interact with HLA. Further studies will be necessary to establish the significance of this association.     

Plasma adiponectin and insulin resistance in Korean type 2 diabetes mellitus

Insulin resistance, which implies impairment of insulin signaling in the target tissues, is a common cause of type 2 diabetes. Adipose tissue plays an important role in insulin resistance through the dysregulated production and secretion of adipose-derived proteins, including tumor necrosis factor-alpha, plasminogen activator inhibitor-1, leptin, resistin, angiotensinogen, and adiponectin. Adiponectin was estimated to be a protective adipocytokine against atherosclerosis, and also to have an anti-inflammatory effect. In this study, the relationship between fasting plasma adiponectin concentration and adiposity, body composition, insulin sensitivity (ITT, HOMAIR, QUICK), lipid profile, fasting insulin concentration were examined in Korean type 2 diabetes. The difference in the adiponectin concentrations was also examined in diabetic and non-diabetic subjects, with adjustment for gender, age and body mass index. 102 type 2 diabetics and 50 controls were examined. After a 12-h overnight fast, all subjects underwent a 75 gram oral glucose tolerance test. Baseline blood samples were drawn for the determinations of fasting plasma glucose, insulin, adiponectin, total cholesterol, triglyceride, LDL-cholesterol, and HDL-cholesterol. The body composition was estimated using a bioelectric impedance analyzer (Inbody 2.0). The insulin sensitivity was estimated using the insulin tolerance test (ITT), HOMAIR and QUICK methods. In the diabetic group, the fasting adiponectin concentrations were significantly lower in men than in women. They were negatively correlated with BMI (r=-0.453), hip circumference (r=-0.341), fasting glucose concentrations (r=-0.277) and HOMAIR (r= -0.233). In addition, they were positively correlated with systolic blood pressure (r=0.321) and HDL-cholesterol (r= 0.291). The systolic blood pressure and HDL-cholesterol were found to be independent variables, from a multiple logistic regression analysis, which influenced the adiponectin concentration. Compared with the non-diabetic group, the adiponectin concentrations were significantly lower in the diabetic group, with the exception of obese males. In conclusion, the plasma adiponectin concentrations were closely related to the insulin resistance parameters in Korean type 2 diabetic patients.     

Apo E 2 phenotypes in type II diabetics with and without insulin therapy

Summary In 106 type II diabetics with persisting hyperlipidemia (i.e persistently increased triglycerides >200 mg/dl during intensive diabetes therapy) the Apo E polymorphism was examined in relation to IDDM (n=68) and NIDDM (n=38). It was shown that Apo E2 phenotypes are more (22.6% vs. 14.5%,p<0.05) and Apo E3 phenotypes less frequent in type II diabetics than in non-diabetic controls (86.8% vs. 94.7%,p<0.001). Looking at the increase in Apo E2 phenotypes it could be proved that the phenotype composition was distinctly different between diabetics with and in those without insulin therapy. While in NIDDM the increase was consequent to a higher concentration of Apo E2 homozygotes (p<0.005) it was caused by Apo E2 heterozygotes in IDDM (p<0.025) accompanied by a simultaneous decrease in Apo E3 homozygotes (p<0.025). Regarding blood lipids there was an increase in total cholesterol due only to VLDL cholesterol in IDDM as well as in NIDDM. It is concluded that in spite of similar hyperlipidemias in type II diabetics the increase in Apo E2 phenotypes is different; it is induced by heterozygotes in IDDM and by homozygotes in NIDDM.Abbreviations PVD peripheral vascular disease - CHD coronary heart disease - IDDM insulin dependent diabetes mellitus - NIDDM non insulin dependent diabetes mellitus - VLDL very low density lipoproteins - LDL low density lipoproteins - HDL high density lipoproteins     

Ischemia-modified albumin in type 2 diabetic patients with and without peripheral arterial disease

OBJECTIVE:

To determine whether there is an association between serum ischemia-modified albumin and the risk factor profile in type 2 diabetic patients with peripheral arterial disease and to identify the risk markers for peripheral arterial disease.

METHODS:

Participants included 290 patients (35.2% women) with type 2 diabetes. The ankle-brachial pressure index was measured using a standard protocol, and peripheral arterial disease was defined as an ankle-brachial index <0.90 or ≥1.3. The basal ischemia-modified albumin levels and clinical parameters were measured and analyzed. The risk factors for peripheral arterial disease were examined by multiple logistic analyses.

RESULTS:

Age, systolic blood pressure, total cholesterol, low-density lipoprotein cholesterol, urine albumin, homocysteine, and ischemia-modified albumin were significantly higher in patients with peripheral arterial disease than in disease-free patients (p<0.05), while ankle-brachial index was lower in the former group (p<0.05). Ischemia-modified albumin was positively associated with HbA1c and homocysteine levels (r = 0.220, p = 0.030; r = 0.446, p = 0.044, respectively), while no correlation was found with ankle-brachial index. Multiple logistic analyses indicated that HbA1c, systolic blood pressure, homocysteine and ischemia-modified albumin were independent risk factors for peripheral arterial disease in the diabetic subjects.

CONCLUSION:

The baseline ischemia-modified albumin levels were significantly higher and positively associated with HbA1c and homocysteine levels in type 2 diabetic patients with peripheral arterial disease. Ischemia-modified albumin was a risk marker for peripheral arterial disease. Taken together, these results might be helpful for monitoring diabetic peripheral arterial disease.     

Impact of intranasal application of nerve growth factor on the olfactory epithelium in rats with chemically induced diabetes

Recent studies suggest that nerve growth factor (NGF) protects olfactory cells and axons from injury in vitro. Eighteen Wistar-Albino rats randomly divided into three groups: control group, diabetic group without NGF, and diabetic with NGF. Intranasal NGF (6 µg/day) was administered over a 5-day period. At the end of 30 days, the olfactory epithelium (OE) of NGF-applied diabetic rats regenerated, the epithelium thickness was significantly higher, and caspase-3 expression was not significantly different from the control. The current results demonstrate that intranasally administered NGF significantly reversed OE morphological changes in diabetes by decreasing diabetes-related cell death and inflammation.     

Preference behavior and taste nerve responses in D-penicillamine treated rats

Preferences for NaCl, sucrose, HCl and quinine were examined in rats fed a diet containing D-penicillamine (D-pen), and compared with those of normal control rats. Preferences for NaCl and sucrose were reduced by administration of D-pen, and returned to normal upon cessation of D-pen administration. Change in preferences for NaCl and sucrose depended on the amount as well as the duration of D-pen administration. Preferences for HCl and quinine were unaffected by D-pen. No significant difference in the threshold and magnitude of the chorda tympani nerve responses to the taste stimuli was found between D-pen treated and normal rats. Concentrations of electrolytes in serum and saliva were scarcely changed by D-pen administration, but the amount of serum copper was markedly reduced. Effect of D-pen on sensitivity of taste receptors and role of copper ions in regulating fluid intake are discussed.