无创遥测技术观察运输应激对Beagle犬部分生理指标的影响

目的应用无创遥测技术观察运输应激对Beagle犬部分生理指标的影响。方法 16只Beagle犬随机分成两组（每组8只）,即对照组和运输应激组,并利用大动物无创生理信号遥测技术,分别监测清醒自由活动状态下对照组和运输应激组应激4 h后Beagle犬的心电图、活动、皮肤温度和呼吸参数的变化。结果 Beagle犬心率、RR间期、QT间期、活动、皮肤温度、呼吸均具有明显的昼夜节律变化（P〈0.01）;与对照组比,运输应激后Beagle犬心率、活动度、呼吸频率、每分钟通气量和潮气量均显著增加（P〈0.01）,RR间期、PR间期、皮肤温度均显著降低（P〈0.01）,相关分析表明运输应激对Beagle犬心率、活动、皮肤温度和呼吸频率具有显著的相关性（P〈0.05,P〈0.01）。结论运输应激可引起Beagle犬生理学指标的明显改变,但除皮肤温度外,运输应激（4 h）对Beagle犬昼夜节律变化破坏不明显;利用无创遥测技术平台可建立理想的Beagle犬生物模型,可用于动物福利和药理毒理学评价研究。     

Methemoglobin reductase activity and in vitro sensitivity towards oxidant induced methemoglobinemia in Swiss mice and Beagle dogs erythrocytes

The NADH methemoglobin-reductase (EC 1.6.2.2) is mainly responsible for the maintenance of hemoglobin in its reduced and active state. The present study reveals the comparative status of this enzyme in normal Beagle dogs, rats, mice, mastomys and hamsters erythrocytes. The spectrophotometric and electrophoretic determinations showed that the above mentioned enzyme was deficient in the Beagle dog's erythrocytes. Furthermore, in vitro studies on the sensitivity of these rodents and Beagle dogs hemolysate towards oxidants, like primaquine and sodium nitrate, depicted a higher level of methemoglobin formation in the Beagle dogs hemolysate as compared to that of the rodent species. The deficiency of methemoglobin reductase in Beagle dogs erythrocytes could be responsible for their increased sensitivity towards oxidant induced methemoglobinemia.     

Alterations in the activities of subcellular fractions marker enzymes in rat liver and brain by hydrocortisone and corticosterone treatment

The effect of subcutaneous injection of hydrocortisone and corticosterone on the activity values of some subcellular fractions marker enzymes from rat liver and brain was investigated and compared with controls (without treatment with hormones). The following enzymes were studied (subcellular fraction are shown between parentheses): N-acetyl-beta-D-glucosaminidase and beta-glucuronidase (lysosomes); succinate dehydrogenase = SDH (mitochondria); glucose-6-phosphatase (endoplasmic reticulum); 5'-nucleotidase and Na+-K+-Mg2+ ATPase (plasma membrane). The specific activity of lysosomal enzymes from liver showed no change when rats were injected either with hydrocortisone or corticosterone. The same enzymes from brain showed significant increases in their activities with both hydrocortisone or corticosterone except beta-glucuronidase; this enzyme gave activity values remaining between the control levels, after treatment with corticosterone. The activity of mitochondrial SDH was increased after corticosterone injection either in liver or brain. After hydrocortisone injection, its activity rises significantly in brain (72%), but it falls in liver compared to the control values. Glucose-6-phosphatase behaves similarly in brain or liver fractions; its activity increases always after corticosterone treatment and decreases by hydrocortisone. The plasma membrane marker enzymes did not change practically in brain fractions, excepted Na+-K+-Mg2+ ATPase which tends to rise its activity after hydrocortisone injection. In liver fractions, both 5'-nucleotidase and Na+-K+-Mg2+ ATPase activities increase either by corticosterone or hydrocortisone treatment, except 5'-nucleotidase which specific activity decreases in liver after hydrocortisone treatment.     

Successive changes in the blood composition of experimental normal beagle dogs associated with age

Eight hematologic parameter values, 16 serum biochemical constituents, serum protein fractions and albumin-globulin ratios were determined in blood samples obtained from 879 normal, healthy Beagle dogs of both sexes which had been reproduced and bred in our laboratories. The blood samples were collected from the Beagles that ranged in monthly ages from 1 to 12 and in monthly ages from 13 to 121, which were classified as the adult class. As a result, red blood cell counts, hemoglobin concentrations and packed cell volumes increased with growth. Red blood cell parameters of normal Beagles in our laboratories were rather higher than those in literatures presented by many other researchers. MCV decreased and MCHC increased gradually with age. Total serum protein concentrations increased with growth. alpha 1-1 and alpha 1-2 Globulin fractions descended, but beta 2 and gamma globulin fractions ascended in serum proteins. Alkaline phosphatase activities, inorganic phosphorus concentrations and glucose concentrations decreased conspicuously with growth. Leucine aminopeptidase activities and calcium concentrations decreased slightly. Serum cholinesterase and LDH activities showed a tendency to diminish similarly. Blood urea nitrogen and creatinine concentrations multiplied gradually. Hematologic parameters became almost steady in our 7-month-old dogs or older ones and serum biochemical constituents had a tendency to be stable in our 7- to 9-month-old dogs or older ones in the blood. White blood cell counts, alkaline phosphatase activities, inorganic phosphorus concentrations, glucose concentrations, leucine aminopeptidase activities and calcium concentrations were lowest in the adult class.     

Liver glycogen metabolism in endotoxin shock. II. Endotoxin administration increases glycogen phosphorylase activities in dog livers

The effects of E. coli endotoxin administration on hepatic glycogen phosphorylase activities in dogs were investigated. Hepatic glycogen phosphorylase activities in both control and endotoxic dogs were inactivated spontaneously by preincubation of enzyme preparations at 25 degrees C. Total glycogen phosphorylase activity was not significantly altered during preincubation. The activity of glycogen phosphorylase a was increased by 83 and 80% at 1 and 2 hr postendotoxin, respectively, without preincubation; and by 203 and 133% at 1 and 2 hr postendotoxin, respectively, after 30 min preincubation. Without preincubation, the glycogen phosphorylase percentage a activity was increased from the control value of 37 to 58% at 1 hr postendotoxin and to 53% at 2 hr postendotoxin. After 30 min preincubation, the glycogen phosphorylase percentage a activity was increased from the control value of 10 to 28% at 1 hr postendotoxin and to 20% at 2 hr postendotoxin. The time required for half maximum inactivation of percentage a activity was 16.5, 33, and 24 min for control, 1 and 2 hr postendotoxin, respectively. Although the Vmax and Km for glucose-1-P for total glycogen phosphorylase were not affected by endotoxin administration, the Vmax for glucose-1-P for glycogen phosphorylase a was increased by 57.3 and 42.7% at 1 and 2 hr postendotoxin, respectively, with no change in the Km values. Glucose inhibited glycogen phosphorylase a activity both in control and endotoxin-injected dogs, but the I50 value was increased by 35% in endotoxin-injected (2 hr) dogs. AMP activated glycogen phosphorylase b activity both in control and endotoxin-injected dogs with no change in A0.5 values between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antibody response of dogs inoculated with a large number of cultured canine monocytes adsorbed with a calicivirus in advance

Five conventional Beagle dogs were intravenously injected with ten million canine monocyte cells (Cn/K99) cultured in vitro (Kadoi, 2000) adsorbed with a strain of calicivirus originally isolated from lions (Kadoi et al., 1997). Another two Beagle dogs were injected similarly with the virus suspension solely as control. Serum samples were collected from these dogs at intervals and specific seroneutralizing antibody production against the virus was measured in vitro. A significantly higher antibody production was demonstrated in the five dogs group. A clear booster effect was also proved in the sera of the dogs after the second virus inoculation made on day 100. A possibility of antigen presentation function of non-self monocytes is suggested.     

Effects of medium containing heparin and theophylline on capacitation and metabolic enzyme activities of ejaculated spermatozoa from dogs with asthenozoospermia

The percentages of motile sperm (%MO), hyperactivated sperm (%HA), and acrosome-reacted sperm (%AR) of four beagle dogs with asthenozoospermia (AS) and five normal beagle dogs were determined during 7 h of incubation. The metabolic enzyme activities of the sperm was examined after 0 and 4 h of incubation. The sperm were incubated in canine capacitation medium (CCM) and CCM containing either 20 microg ml(-1) heparin (HE), 10 microg ml(-1) theophylline (TH) or 20 microg ml(-1) HE + 10 microg ml(-1) TH in glass tubes at 38 degrees C under 5% CO2 in air. The %HA and %AR were determined by counting the sperm exhibiting star-spin like movement and by the triple stain technique. The spermatozoa in HE + TH CCM were homogenized and centrifuged, and the metabolic activities of hexokinase, fructokinase, glucose-6-phosphodehydrogenase (G6PD), and pyruvate kinase in the sperm cytosol in the supernatant was measured with a spectrophotometer. The mean %MO and %HA values of both AS and normal dogs in the four types of CCM were highest in HE + TH CCM, with a mean %HA in HE + TH CCM of 78 +/- 5% (S.E.) after 7 h of incubation. However, there was little difference in %AR among the four types of CCM. The mean activities of the four enzymes in the sperm of AS dogs before incubation was significantly lower than in the sperm of normal dogs (P < 0.05, 0.01). However, after 4 h of incubation the activities of all enzymes in the sperm of both AS and normal dogs was clearly higher in HE + TH CCM than in the control CCM. These findings indicate that HE and TH in the medium are effective inactivating metabolic enzymes, maintaining longer sperm motility, and efficiently inducing HA even of the sperm of AS dogs.     

Some Effects of a Low Sodium Diet High in Potassium on the Renin-Angiotensin System and Plasma Electrolyte Concentrations in Normal Dogs

Eight normal male Beagle dogs received 0.7 mmol Na+/kg/day for 5 weeks and 4.0 mmol Na+/kg/day in one 3 week control period preceding and another similar period following the low sodium period. The dogs received 6.8 mmol K+/kg/day throughout the study. The median plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were higher in the low sodium period than in the following control period (0.67 versus 0.28 ng/ml/h, p < 0.0001) and (204 versus 31 pg/ml, p < 0.0001). PRA and PAC quickly stabilized on a new steady level in response to altered intake of sodium chloride. The angiotensin-converting enzyme (ACE) activity was not changed by the altered intake of sodium chloride. The plasma concentrations of sodium and chloride were increased during the low sodium period. This could be due to an indirect effect of the high potassium intake of the dogs. Potassium leads to an increased secretion of aldosterone and thereby to an increased retention of sodium and chloride in the kidney. The possible implications of a high potassium content in a low sodium diet are discussed.     

Temporal changes in prolactin and corticosterone response during chronic treatment with d-fenfluramine

In order to elucidate the mechanism of development of tolerance to the anorectic effect during chronic treatment with d-fenfluramine (d-F), we examined the temporal changes induced by d-F in food intake and prolactin (PRL) and corticosterone secretion. Male Sprague-Dawley rats were treated for 14 days with d-F (2.5 mg/kg i.p.) or saline twice daily and were given free access to food and water. Groups of 8 rats were sacrificed 30 min after d-F or saline injection at days 1, 4 and 14 for measurements of serum PRL and corticosterone. Food intake and weight gain were reduced significantly by d-F during the first 2-3 days of treatment but not thereafter. Compared with saline, d-F initially increased PRL (57 +/- 9 vs. 7 +/- 0.7 ng/ml) and corticosterone (42 +/- 2 vs. 14 +/- 3 micrograms/dl) serum concentrations. At 4 days, PRL was still significantly increased (43 +/- 5 vs. 10 +/- 4 ng/ml) but corticosterone returned to basal levels. At 14 days, PRL and corticosterone concentrations in the d-F group were not different from corresponding values in the saline group. To verify whether the loss of corticosterone and PRL responses to d-F was not due to a depletion of hormone stores, direct stimulation of corticosterone with corticotrophin and of PRL with metoclopramide were made at days 4 and 14, respectively. Corticotrophin (0.25 mg/kg i.p.) increased corticosterone concentrations similarly in d-F-treated (45 +/- 8 micrograms/dl) and in saline-treated rats (51 +/- 7 micrograms/dl).(ABSTRACT TRUNCATED AT 250 WORDS)     

一种比格犬雌二醇β受体剪切异构体的克隆和序列分析

目的分析比格犬下丘脑-垂体-性腺轴,雌二醇β受体剪切异构体的存在情况。方法根据NCBI数据库上的比格犬雌二醇受体的基因序列,设计两对特异性引物,以比格犬的卵巢、子宫、下丘脑和垂体的总RNA为模板进行反转录,并利用两对特异性引物扩增比格犬雌二醇受体的基因,对其中的主要条带进行克隆测序。结果获得了比格犬雌二醇受体的全长cDNA序列,对主要条带进行克隆测序的结果表明,该序列是一种比格犬雌二醇受体的剪切异构体。结论比格犬雌二醇β受体剪切异构体与小鼠和人的组成有较大的不同,需要进一步系统研究。     

Kinetic aspects of enzyme activity changes in blood plasma during canine hemorrhagic shock

The kinetics of the increase in activities of eight enzymes in plasma was investigated in hemorrhagic shock in dogs (8.0 kPa, 120 min). The time-course of enzyme activity changes in shock differed between animals and depended on their sensitivity to shock. In the shock-sensitive group of dogs an exponential activity increase was already observed in the hypotension period. However, the dogs of the less shock-sensitive group showed a delay of enzyme release with significantly less pronounced elevation of all enzyme activities except creatine kinase. The initial exponential rise of enzyme activities, which approximately followed first-order kinetics, was quantitatively characterized by the release rates. There was a close correlation between the molecular weights of enzymes and their release rates during shock in both groups of dogs. The relevance of the results to mechanisms of enzyme transport from the cell into the blood is discussed.     

成年Beagle犬生物学指标及心电图检测值统计分析

目的 测定正常Beagle犬生理指标,比较不同性别间各参数的差异,以建立健康成年Beagle犬相关生理学参数的基础正常值.方法 根据国家(成都)中药安全性评价中心制定的标准操作规程(SOP)并参照国内外相关资料,对200只4～8月龄Beagle犬的心电图、血压、呼吸、血液学及血液生化等指标进行检测.结果 200只犬均为窦性心律,雌性犬心率较雄性快(P<0.01);血液学指标中RBC、Hb及HCT值雌性均低于雄性,差异有统计学意义(P<0.01);血生化指标中雌性犬高于雄性的是BUN(P<0.05);雌性犬低于雄性的是TP、ALB、GLU、TC及K+的含量(P<0.05或P<0.01).结论 在本实验室条件下,雌雄Beagle犬之间部分指标有统计学差异,本结果可为Beagle犬的实验提供正常值参考.     

The Effect of Exercise on Blood Parameters in Standardbred and Finnish-Bred Horses

Serum enzyme activities, albumin, protein, urea, cholesterol, triglyceride, free fatty acid, glucose and lactate concentrations as well as hematocrit values were measured in standardbred and Finnish-bred horses at rest and after (i) a short controlled exercise and (ii) a trotting competition. There were no breed differences in the enzyme activities at rest and the 2 breeds responded in the same manner to the exercise. Only after the race proper significant increases in the enzyme activities were found. The activities rose more in the standardbred horses than in the Finnish-bred horses. Urea and cholesterol concentrations did not change after either exercise. Protein and albumin concentrations as well as hematocrit values increased significantly after the exercise. At rest hematocrit values were significantly higher in the standardbred horses and the difference persisted throughout the exercise. After the race proper also albumin and protein concentrations were higher in the standard-bred than in the Finnish-bred horses. Free fatty acid and triglyceride concentrations increased significantly during the exercise. Although glucose and lactate concentrations increased in both breeds, the behaviour of these parameters differed. Glucose concentrations remained increased for a longer period and the recovery from the increased lactate level was faster in the standardbred than in the Finnish-bred horses. The observed differences suggest that the standardbred horses have higher anaerobic capacity than the Finnish-bred horses.     

The haemodynamic and catecholamine response to xenon/remifentanil anaesthesia in Beagle dogs

The noble gas xenon seems to have minimal cardiovascular side-effects and so may be an ideal anaesthetic agent when investigating cardiovascular physiology. In comparison with standard modern anaesthetics, we investigated the haemodynamic and hormonal effects of xenon in Beagle dogs. After a 30 min baseline period, anaesthesia was induced with propofol and maintained with either (1) 1.2% isoflurane/70% nitrous oxide (N(2)O), (2) 0.8% isoflurane/0.5 microg/kg/min remifentanil or (3) 63% xenon/0.5 microg/kg/min remifentanil (n = 6 per group). Haemodynamics were recorded and blood samples taken before and 60 min after induction. Mean arterial blood pressure (MAP) was higher in conscious dogs than during isoflurane/N(2)O (86 +/- 2 vs. 65 +/- 2 mmHg, mean +/- SEM) and isoflurane/remifentanil anaesthesia (95 +/- 2 vs. 67 +/- 3 mmHg), whereas MAP did not decrease significantly in response to xenon/remifentanil anaesthesia (96 +/- 4 vs. 85 +/- 6 mmHg). Bradycardia was present during isoflurane/remifentanil (54 +/- 2/min) and xenon/remifentanil (40 +/- 3/min), but not during isoflurane/N(2)O anaesthesia (98 +/- 3/min, P < 0.05). Xenon/remifentanil anaesthesia induced the highest reduction in cardiac output (CO) (-61%), and the highest increase in systemic vascular resistance (+120%) among all treatment groups (P < 0.05). A simultaneous increase in endogenous adrenaline and noradrenaline concentrations could only be observed in the xenon/remifentanil group, whereas angiotensin II and vasopressin concentrations increased in all groups. In conclusion, xenon/remifentanil anaesthesia maintains MAP but reduces heart rate and CO and is associated with a considerable stimulation of vasopressor hormones in Beagle dogs. Therefore, xenon/remifentanil exerts a new quality of adverse haemodynamic effects different from volatile anaesthetics and may not perform better during studies of cardiovascular physiology.     

Enzyme activities in thoracic duct lymph and plasma of anaesthetized, conscious resting and exercising dogs

The significance of changes in lymph flow for the extracellular distribution and transport of cellular enzymes and for the level of enzyme activities in plasma was investigated. Specimens of thoracic duct lymph were obtained from an extracorporal lymph shunt in anaesthetized, conscious resting and treadmill exercising dogs (6 km X h-1 for 1 h) The activity of 10 enzymes and of protein content in lymph and plasma were studied, as well as lymph flow, lymphatic transport, and the lymph-plasma ratio of these compounds. Lactate, pH, and blood gases were monitored in venous blood. Lymph flow of 0.80 ml X min-1 in anaesthetized dogs more than doubled (to 1.86 ml X min-1) when the animals were conscious and resting. In anaesthetized dogs lymph enzyme activity was higher only for enzymes of predominately hepatic origin, such as choline esterase (CHE) and alanine aminoferase (ALAT), and was lower for aspartate aminotransferase (ASAT) and aldolase (ALD). In conscious dogs, due to activation of the skeletal muscle "tissue pump", lymphatic transport of enzymes with rather high activity in skeletal muscle, and of protein, is significantly enhanced. Enzyme activities in plasma, however, did not differ between the groups. Lymph-plasma activity ratios higher than one were found for lactate dehydrogenase (LDH), malate dehydrogenase (MDH), ASAT, creatine kinase (CK), ALD, and phosphohexose isomerase (PHI). Exercise stimulated lymph flow up to 4.9 ml X min-1, and increased the lymphatic activities of those enzymes with a lymph-plasma ratio higher than unity, these enzymes increasing in the plasma due to the highly increased lymphatic transport.(ABSTRACT TRUNCATED AT 250 WORDS)     

Renal function and morphology in aged Beagle dogs before and after hydrocortisone administration

Objectives of this study were to evaluate glomerular filtration rate (GFR), renal structural changes and proteinuria in aged Beagle dogs before and after hydrocortisone (HC) administration. Eleven Beagle dogs ≥10 years old were treated with either hydrocortisone (HC group, n = 6) or placebo (control group, n = 5). Urinary markers, GFR and kidney biopsies were evaluated before (T0), during (T16 wks) and after discontinuing HC administration (T24 wks). Results indicate that HC administration causes a significant increase in GFR. At all time points except T16 wks, proteinuria was higher in the control group than in the HC group, and there was no significant difference in urinary markers between groups. At T16 wks, proteinuria, urinary albumin-to-creatinine (c) ratio, immunoglobulin G/c and retinol-binding protein/c were higher compared to baseline in the HC group. At T0, rare to mild renal lesions were detected in all HC dogs and rare to moderate changes in all control dogs. Glomerulosclerosis progressed in both groups until T24 wks. Tubular atrophy was detected in three HC dogs at T16 wks and T24 wks, but also in five control dogs throughout the study. At every time point, five HC dogs and all control dogs had rare to moderate interstitial inflammation. Rare to mild interstitial fibrosis was found in up to three HC dogs at T16 wks and T24 wks, and severe fibrosis in one HC dog at T24 wks. Up to four control dogs had rare to mild fibrosis at all time points. These findings indicate that clinically healthy, aged Beagle dogs may have considerable renal lesions and proteinuria, which could have implications for experimental or toxicological studies. Additional research is needed to elucidate glucocorticoid effects on renal structure, but functional changes such as hyperfiltration and proteinuria warrant attention to kidney function of canine patients with Cushing''s syndrome or receiving exogenous glucocorticoids.     

Effect of aerial exposure on the antioxidant status in the subantarctic stone crab Paralomis granulosa (Decapoda: Anomura)

In Tierra del Fuego (Southern South America), the stone or false king crab, Paralomis granulosa represents one of the most important crab fisheries. After capture, animals are kept in baskets and exposed to dryness for several hours, when the water flow through the gills is interrupted. As a consequence a concomitant increase of reactive oxygen species begins, triggering oxidative stress. The aim of this study was to determine oxidative stress and antioxidant enzyme activities due to air exposure in different tissues of P. granulosa. Fifty crabs (carapace length >82 mm) were captured in Beagle Channel (54 degrees 50'S, 68 degrees 20'W) during winter 2004. Five groups of 10 crabs each were exposed to dryness at 6 degrees C for 0, 3, 6, 12 or 24 h, respectively. Activity of superoxide dismutase (SOD), catalase (CAT), glutathione S transferase (GST) protein and lipid oxidation were measured in gills, muscle, hepatopancreas and haemolymph samples. Almost all analyzed tissues showed antioxidant enzymes activity, which varied with time of air exposure. The maximum enzyme activity was measured after 6 h of air exposure. Protein oxidation levels varied significantly in gills. Lipid peroxidation levels increased significantly in muscle and hepatopancreas. The critical time of air exposure probably occurs at 6 h. Thereafter animals were unable to induce the synthesis of antioxidant enzymes or proteins. This should be taken into account to minimize the stress generated by the commercial capture process.     

皮质酮对大鼠再生肝细胞鸟氨酸脱羧酶活性及其基因表达的影响

采用高效液相色谱和原位杂交技术研究了皮质酮对大鼠再生肝细胞鸟氨酸脱羧酶 (ODC)活性及ODCmRNA表达的影响。结果显示 ,大鼠完整肝脏中ODC水平较低 ,2 / 3肝切除 (PH)后 3h ,不同处理组ODC活性开始升高 ,6h达到最高值 ,其中 ,去肾上腺 NaCl组和糖皮质激素受体拮抗剂RU4 86处理组的酶活性高于对照组 (去肾上腺假手术组 ) ,而去肾上腺 皮质酮处理组的酶活性低于对照组 ,36h恢复到肝切除前水平 ;完整肝脏的ODCmRNA水平极低 ,PH后表达量迅速增加 ,5h达到最大值 ,不同处理组mRNA水平的高低顺序与酶活性一致 ,12h降至肝切除前水平 ;在PH前 12h给大鼠注射RU4 86 (10mg/kg体重 ) ,取得了与去肾上腺 NaCl处理鼠相似的结果。以上结果表明 ,在PH诱导的再生肝细胞中 ,ODCmRNA表达量的增加和 /或减少是造成ODC活性改变的原因之一 ,皮质酮对ODC活性及其mRNA的表达具有抑制作用 ,主要表现在肝再生的早期 ,该作用可能是通过受体实现的     

Theme D: The Refinement of Animal Procedures

This study investigated the physiological reactions of companion dogs (Canis familiaris) used in animal-assisted activities and animal-assisted therapy by measuring salivary cortisol concentrations. The dog caregivers (owners) collected saliva samples (a) at 3 control days without therapeutic work, (b) directly before and after each therapeutic session during 3 consecutive months, and (c) again at 3 control days without therapeutic work. The study used an enzyme immunoassay to analyze the samples. Cortisol concentrations were significantly higher during therapy days than on control days. Dogs working during the first half of the day produced higher cortisol concentrations after therapeutic sessions than before, whereas dogs working in the afternoon produced lower cortisol concentrations. Cortisol concentrations were higher in short sessions than in long ones and increased relative to the number of therapeutic sessions done during the sampling period. The results indicate that therapeutic work was physiologically arousing for the dogs in this study. Whether these physiological responses are indicative of potentially negative stress or of positive excitement remains an open question.     

Physiological arousal for companion dogs working with their owners in animal-assisted activities and animal-assisted therapy

This study investigated the physiological reactions of companion dogs (Canis familiaris) used in animal-assisted activities and animal-assisted therapy by measuring salivary cortisol concentrations. The dog caregivers (owners) collected saliva samples (a) at 3 control days without therapeutic work, (b) directly before and after each therapeutic session during 3 consecutive months, and (c) again at 3 control days without therapeutic work. The study used an enzyme immunoassay to analyze the samples. Cortisol concentrations were significantly higher during therapy days than on control days. Dogs working during the first half of the day produced higher cortisol concentrations after therapeutic sessions than before, whereas dogs working in the afternoon produced lower cortisol concentrations. Cortisol concentrations were higher in short sessions than in long ones and increased relative to the number of therapeutic sessions done during the sampling period. The results indicate that therapeutic work was physiologically arousing for the dogs in this study. Whether these physiological responses are indicative of potentially negative stress or of positive excitement remains an open question.