Biological features of the skin of the pika, Ochotona rufescens rufescens: histological structure and enzymatic histochemical reactivity

To examine the usefulness of the pika, Ochotona rufescens rufescens, as an experimental animal for skin irritability tests, the histological structure and enzymatic histochemical reactivity of pika skin were investigated. The pika had a hair cycle similar to that of the rabbit. The skin and epidermis of the pika trunk were 1.16mm and 29.5 microns thick, on the average, respectively. Both of them were the thickest in the dorsal region followed by the interscapular area, while they were the thinnest in the abdominal region. In the epidermis of the pika, the strata corneum, granulosum, spinosum and basale were rather clearly distinguished. The cell arrangement in the stratum basale was more compact than that in the rabbit. Dermal mast cells, which are distributed in the stratum reticulare in rabbits and guinea pigs, were distributed in the stratum papillare right beneath the epidermis. The mast cell of the pika in the TEM images had granules of low electron density and with relatively long microvilli and rather large mitochondria. The activities of the enzymes, SDH, MDH, LDH, beta HBDH, alpha GPDH, ALD, G6PDH and GPR, in the hair follicles and sebaceous glands of the pika were similar to those of the rabbit.     

Association between histamine-containing mast cells and sensory nerves in the skin and airways of control and capsaicin-treated pigs

Summary The association between mast cells (visualized by routine staining and immunohistochemistry for histamine) and capsaicin-sensitive nerves (containing calcitonin gene-related peptide (CGRP) and substance P (SP)) was studied in the pig. In the 1-ethyl-3(3-diethylaminopropyl)carbodiimide (EDCDI)-fixed skin tissue, histamine-containing mast cells and CGRP/SP-positive nerves were found in close association around blood vessels. In the EDCDI-fixed airway mucosa, only single histamine-containing mast cells were detected. However, many alcian blue-positive mast cells were found, sometimes close to the airway epithelium where CGRP/SP-containing nerve fibres were absent 2 days after systemic capsaicin pretreatment, but no changes in the number and distribution of tissue mast cells, granulocytes or lymphocytes, or the number of blood leukocytes were detected. Local injection of allergen, histamine and capsaicin into the skin of pigs actively sensitized with ascaris antigen caused a rapid light red-flare (vasodilation) reaction. Allergen and histamine, but not capsaicin, also produced plasma protein extravasation. In contrast to the absent flare, the protein extravasation response still occurred in capsaicin-treated pigs. The sensitivity to ascaris antigen was mediated by an IgE-like antibody. We conclude that a functional and morphological relationship exists between histamine-containing mast cells and capsaicin-sensitive sensory nerves in the pig skin. Mast cells and sensory nerves are also found in the airway mucosa and appear to be closely associated with the epithelium.     

In vitro and inhibition of anaphylactic reactions 1-methyl-3-isobutylxanthine]

1-methyl-3-isobutylxanthine (MIBX), a potent antiphosphodiesterase drug, inhibited the anaphylactic reactions both in vitro and in vivo: anaphylactic histamine release from the isolated mast cells of rats, anaphylactic contracture of the isolated trachea of guinea pigs, passive cutaneous anaphylaxis (PCA) in mice and anaphylactic bronchial constriction (ABC) in guinea pigs. MIBX inhibited the anaphylactic reaction of the trachea, PCA and ABC more than the corresponding reactions induced by histamine.     

Study on systemic reaction of delayed type hypersensitivity

Effectiveness of two different samples of PPD tuberculins was studied quantitatively. No differences were found in the effect on skin test in rabbits, extent of skin reaction in guinea pigs, edema of foot-pad in rats and inhibition of spleen cell migration in guinea pigs. Differences were observed in the systemic febrile reaction in rabbits and in examinations of the thickness of infiltrated skin in guinea pig tests. The results may serve as a basis for standardization of systemic reaction in rabbits.     

Histamine Turnover in the Brain of Different Mammalian Species: Implications for Neuronal Histamine Half-Life

The turnover of neuronal histamine (HA) in nine brain regions and the spinal cord of the guinea pig and the mouse was estimated and the values obtained were compared with data previously obtained in rats. The size of the neuronal HA pool was determined from the decrease in HA content, as induced by (S)-alpha-fluoro-methylhistidine (alpha-FMH), a suicide inhibitor of histidine decarboxylase. The ratios of neuronal HA to the total differed with the brain region. Pargyline hydrochloride increased the tele-methylhistamine (t-MH) levels linearly up to 2 h after administration in both the guinea pig and the mouse whole brain. Regional differences in the turnover rate of neuronal HA, calculated from the pargyline-induced accumulation of t-MH, as well as in the size of the neuronal HA pool, were more marked in the mouse than in the guinea pig brain. The hypothalamus showed the highest rate in both species. There was a good correlation between the steady-state t-MH levels and the turnover rate in different brain regions. Neither the elevation of the t-MH levels by pargyline nor the reduction of HA by alpha-FMH was observed in the spinal cord, thereby suggesting that the HA present in this region is of mast cell origin. The half-life of neuronal HA in different brain regions was in the range of 13-38 min for the mouse and 24-37 min for the guinea pig, except for HA from the guinea pig hypothalamus, which had an extraordinarily long value of 87 min. These results suggest that there are species differences in the function of the brain histaminergic system.     

常用实验动物不同组织部位肥大细胞异质性的组织学特点比较

目的探讨并比较六种常用实验动物不同部位肥大细胞异质性的形态学特点。方法应用麻醉后处死的方法,取小鼠、大鼠、豚鼠、兔、犬和猴的皮肤、肺脏、乙状结肠和脾脏组织,经4%中性缓冲甲醛溶液或Bouin’s液固定后,制作常规组织切片,分别作HE、甲苯胺蓝、阿尔新蓝-藏红和P物质免疫组织化学染色,镜下观察并应用彩色病理图像分析软件进行形态学分析;另取皮肤组织固定于磷酸缓冲戊二醛溶液,制作常规超薄切片,透射电镜下观察肥大细胞超微结构。结果六种动物不同组织中肥大细胞各有其分布特点,且在形态大小、异染性及染色特性等方面表现各异,肥大细胞密度和形态学参数差异有显著性（P〈0.05）;豚鼠、犬和猴皮肤肥大细胞颗粒具有特殊亚微结构;小鼠皮肤组织内可见P物质免疫阳性肥大细胞和神经纤维,犬脾脏内可见P物质免疫阳性肥大细胞。结论在六种实验动物的同一组织中以及同一种动物不同组织中,肥大细胞具有明显的异质性,此异质性对采用实验动物开展与肥大细胞功能相关的动物实验研究具有重要参考价值。     

Comparison of tracheal mucous transport in rats, guinea pigs, rabbits, and dogs

Tracheal mucous transport was measured using similar techniques in several species. One- to 10-microliter quantities of 99mTc-macroaggregated albumin (99mTc-MAA) were instilled via oral intubation in the distal trachea of rats, rabbits, and dogs. Tracheostomies were used for the instillation in guinea pigs. All animals were anesthetized with halothane for the instillation and allowed to recover immediately in restrainers. Clearance of the 99mTc-MAA in rats and guinea pigs was measured by a slit-collimated NaI scanner. In rabbits and dogs a series of gamma-camera scintiphotos were taken. Clearance was faster and more efficient in dogs than in the other species. No significant differences existed among the rats, rabbits, and guinea pigs in the percentages of the originally deposited material remaining at the instillation site after 1 h (P greater than 0.2). Mean values and standard deviations were 83 +/- 23%, 81 +/- 22% and 70 +/- 20% for rats, guinea pigs, and rabbits, respectively. However, in the dogs a mean of 14 +/- 12% remained at the original site of deposition after only 25 min indicating much more rapid clearance. Mean leading-edge velocities were 9.8 +/- 2.1 (SD) for dogs, 3.2 +/- 1.1 for rabbits, 2.7 +/- 1.4 for guinea pigs, and 1.9 +/- 0.7 mm/min for rats. Clearance patterns qualitatively among the species. In dogs the material moved as a few discrete boluses, whereas in the other species the activity spread toward the larynx. The relatively slow mucous transport of rats, rabbits, and guinea pigs could have important implications in inhalation toxicological studies.     

BN大鼠和豚鼠对卵清白蛋白致主动过敏反应的免疫学特性比较

目的 比较BN大鼠和豚鼠对卵清白蛋白(OVA)致敏前后机体免疫学特性的变化.方法 BN大鼠和豚鼠分别用OVA(每只1 mg)隔日致敏(i.p.),共5次;于末次致敏第10天以OVA(每只2 mg)激发致敏(i.v.);分别设正常对照组和OVA致敏组.于激发致敏后1h处死动物,分离腹腔肥大细胞、脾脏和骨髓,并制备脾脏和骨髓淋巴细胞.以annexin-V作为标志检测肥大细胞活性,同时以Fluo-3/AM标记胞内钙离子,检测钙离子水平;以PHA和LPS作为有丝分裂原,分别检测脾脏和骨髓T、B淋巴细胞活性.结果 ①致敏BN大鼠和豚鼠脾脏及骨髓T、B淋巴细胞活性均升高,其中骨髓淋巴细胞活性BN大鼠显著高于豚鼠,脾脏淋巴细胞活性两种属间差异无显著性;②致敏后,腹腔肥大细胞活性两种属间差异无显著性,但BN大鼠致敏后是致敏前的6倍,豚鼠是3倍;③肥大细胞内钙离子水平两种属致敏后均升高,豚鼠致敏前后钙离子水平具有统计学意义.结论 OVA致敏后,BN大鼠骨髓淋巴细胞活性明显高于豚鼠,豚鼠肥大细胞内钙离子较BN大鼠升高明显,肥大细胞活性两者无明显差异.因此,在实验中可以根据两种属在过敏反应中的特点以及具体的实验要求选择动物模型.     

Correlation of Propionibacterium acnes Populations with the Presence of Triglycerides on Nonhuman Skin

The skins of mice, rats, rabbits, sheep, guinea pigs, and dogs were cultured for Propionibacterium acnes. Only the sebaceous regions (perianal gland) of guinea pigs harbored a significant P. acnes population. Analysis of the lipid from this region revealed a significant percentage of triglycerides, compounds lacking in the sebum of the other animals.     

Comparative study of ethynyloestradiol metabolism in the rabbit, guinea pig and rat.

Ethynyloestradiol was administered to rabbits, guinea pigs and rats, and the concentration of the steroid in blood was measured by radioimmunoassay. In both rabbits and guinea pigs, levels of conjugated steroid were much higher than those of the freely extractable form. Whereas considerable amounts of steroid were present in a congugated form in plasma 24 h after injection, none was present at this time in a freely extractable form. There were significant differences between young and adult rabbits and guinea pigs in the rate at which ethynyloestradiol was metabolized. The amounts present in the freely extractable form in rats were higher than in the other two species but no steroid was detected in the conjugated fraction. The results are compared with previous findings in humans.     

Antigen inhalation induces mast cells and eosinophils infiltration in the guinea pig esophageal epithelium involving histamine-mediated pathway

Antigen challenge in sensitized guinea pig esophagus in vitro induces mast cell degranulation and histamine release. This study tests the hypothesis that antigen inhalation in vivo induces infiltration of the esophageal epithelium by mast cells and eosinophils via a histamine pathway. Actively sensitized guinea pigs were exposed to inhaled 0.1% ovalbumin. One or 24 h after inhalation exposure, the esophagus was processed for immunofluorescent staining of mast cell tryptase and eosinophil major basic protein (MBP). Additional animals were pretreated with thioperamide, a histamine H4/H3 receptor antagonist. Total tryptase- and MBP-labeled cells and percent of positive cells in the epithelial layer were counted. The total number of mast cells was unchanged after inhalation challenge, but the percentage in the epithelium increased 1 h after challenge. The total number of eosinophils increased 1 h after challenge, and the percentage migrating to the epithelium increased by 24 h after challenge. Mast cell migration into the mucosal epithelium preceded that of eosinophils. Thioperamide inhibited mast cell and eosinophil migration. In conclusion, antigen inhalation in sensitized animals induces mast cells and eosinophils to infiltrate in the esophageal epithelium via histamine-mediated mechanism.     

Subcellular localization of brain mast cell histamine in developing rat

The intracerebroventricular administration of compound 48/80 or polymixin B to rats 0 to 60 days old, produced a decrease both in the histamine which sediments in the crude nuclear fraction, as well as in the number of mast cells in the brain. In contrast, the histamine-releasers did not affect histamine levels in subcellular fractions where neuronal histamine is found. Once released, histamine disappeared rapidly (t 1/2 = 3.8 min). In untreated animals and in those treated with histamine releasers, the number of mast cells/g in the whole brains of developing rats and in the cerebral regions of adult rats showed a close correlation with the histamine levels in the crude nuclear fraction. The content of histamine per mast cell in adult rat brain was estimated to be about 13 pg/cell. Histologic examination of the subcellular fractions revealed the presence of intact mast cells in the crude nuclear fraction obtained from untreated animals, and of degranulated mast cells in the same fraction obtained from animals treated with histamine releasers. The mast cell contribution to adult rat brain histamine levels was about 22%. Our results strongly support that most of the histamine which sediments in the crude nuclear fraction of the rat brain is located in mast cells. Determination of histamine in the crude nuclear fraction and in the supernatant of this fraction is proposed as an easy way for identifying the cellular pool altered by any treatment affecting brain histamine levels.     

Antiallergic/antiasthmatic effect of novel antiallergic hexapeptide-95/220 in various experimental models

The effects of newly synthesized antiallergic hexapeptide 95/220 was investigated on various allergic and asthmatic test models. This newly developed peptide was found to be more potent than clinically used drug disodium cromoglycate (DSCG). Hexapeptide 95/220 inhibited immediate hypersensitivity reactions such as passive cutaneous anaphylaxis (PCA) and mast cell degranulation in rats, antigen-induced bronchoconstriction in actively sensitized guinea pigs in dose dependent manner like DSCG. Antigen-induced contraction of guinea pig ileum was also markedly inhibited by this newly developed hexapeptide in the same fashion as ketotifen and DSCG did but at comparatively lower dose. Egg albumin-induced histamine release was also blocked by this hexapeptide from chopped lung tissues of sensitized guinea pigs. These results suggest that hexapeptide' 95/220 has potent inhibitory effect on immediate hypersensitivity reactions thereby inhibiting mediator release from mast cell. Moreover, this newly synthesized peptide is orally active and effective at lower doses as compared to standard drugs.     

Brain Histaminergic System in Mast Cell-Deficient (Ws/Ws) Rats: Histamine Content, Histidine Decarboxylase Activity, and Effects of (S)α-Fluoromethylhistidine

Abstract: The mast cell-deficient [ Ws/Ws ( W hite spotting in the skin)] rat was investigated with regard to the origin of histamine in the brain. No mast cells were detected in the pia mater and the perivascular region of the thalamus of Ws/Ws rats by Alcian Blue staining. The histamine contents and histidine decarboxylase (HDC) activities of various brain regions of Ws/Ws rats were similar to those of +/+ rats except the histamine contents of the cerebral cortex and cerebellum. As the cerebral cortex and cerebellum have meninges that are difficult to remove completely, the histamine contents of these two regions may be different between Ws/Ws and +/+ rats. We assume that the histamine content of whole brain with meninges in Ws/Ws rats is <60% of that in +/+ rats. So we conclude that approximately half of the histamine content of rat brain is derived from mast cells. Next, the effects of ( S )α-fluoromethylhistidine (FMH), a specific inhibitor of HDC, on the histamine contents and HDC activities of various regions of the brain were examined in Ws/Ws rats. In the whole brain of Ws/Ws rats, 51 and 37% of the histamine content of the control group remained 2 and 6 h, respectively, after FMH administration (100 mg/kg of body weight). Therefore, we suggest that there might be other histamine pools including histaminergic neurons in rat brain.     

Interspecies differences in rhodanese (thiosulfate sulfurtransferase, EC 2.8.1.1) activity in liver, kidney and plasma

Rhodanese levels have been measured in liver, kidney and plasma from a number of species. Liver activity was low in marmosets, pigeons and beagle bitches. Levels were high in rats and somewhat lower in hamsters and guinea pigs while levels in two strains of rabbits were intermediate between guinea pigs and marmosets. The relationship between hepatic and plasma rhodanese and cyanide sensitivity is discussed.     

Pharmacological profile of AA-861, A 5-lipoxygenase inhibitor

AA-861, a selective 5-lipoxygenase inhibitor, suppressed A23187-induced formations of 5-HETE and LTB₄ in rat peritoneal macrophages. Immunologically-stimulated generation of SRS-A was also inhibited in guinea pig lung and rat peritoneal cavity. AA-861 had no effects on histamine release from rat mast cels or passive cutaneous anaphylaxis in rats. Essentially no antagonistic activity to LDT₄ or histamine was observed. This compound exerted an obvious inhibition of allergic bronchoconstriction in guinea pigs and a moderate reduction of carrageenin-induced paw edema and pleurisy in rats. These findins suggest that SRS-A plays an important role in asthmatic and inflammatory reactions.     

Species difference in increased vascular permeability by synthetic leukotriene C4 and D4

The activity of synthetic LTC₄ was tested in guinea-pig ileum and was 200 times more potent than histamine in contraction of the ileum (3 × 10^?11 M- 3 × 10^?9 M). The activities of LTC₄ and LTD₄ in increased vascular permeability in guinea pigs, rats and rabbits were compared with those histamine, bradykinin and prostaglandin (PG) E₂. LTC₄ was approximately equipotent to bradykinin on a molar basis in guinea pigs and rats and 5–100 times more potent than histamin. LTD₄ was about 10 times more potent than LTC₄ in guinea pigs and as equipotent to LTC₄ in rats. On the contrary, in rabbits, neither LTC₄ (upto 30 nmole/site) nor LTD₄ (1 nmole/site) induced the dye exduation. These results show that species difference is present in activity of LTC₄ and LTD₄ in vascular permeability. Furthermore, in guinea pigs, the vascular permeability increased by LTC₄ was not affected after pretreatment with pyrilamine (2.5 mg/kg, i.v.), and LTC₄ and LTD₄ did not potenciate the activity of bradykinin in vascular permeability.     

Pigmentation in intrinsically aged skin of A1 guinea pigs

It is known that skin often shows irregular pigmentation during aging which is frequently associated with hyperpigmentation. Many studies have utilized brownish A1 guinea pigs to investigate the pathogenesis of ultraviolet (UV)-induced skin pigmentation, however, changes associated with intrinsic aging in A1 guinea pig skin have not been documented. To characterize such changes, skin from the dorsal and neck areas of 20-week, 1-, 2-, 3- and 5-yr-old guinea pigs was examined. Skin color was measured using a colorimeter, and biopsy specimens were stained with Masson-Fontana, L-3,4-dihydroxyphenylalanine (DOPA), and antibodies against KIT (ACK-45), gp100 (HMB-45) and S-100 proteins. The L* value of skin color decreased with aging and melanin deposits increased in the epidermis. Further, DOPA+, gp100+ and S-100+ melanocytes increased, indicating that the number of melanocytes had increased with age, whereas KIT+ melanocytes did not increase in dorsal skin and actually decreased in neck skin with aging. Further, rippled pigmented areas appeared in the neck skin of the 3-yr-old animals, and in the dorsal and neck skin of 5-yr-old guinea pigs in the absence of UV irradiation. Melanocytes were distributed uniformly in younger skin, whereas they were clustered in older skin. UV irradiation caused an increase in the number of melanocytes, although they were not clustered. These results are the first to provide evidence that pigmentation is induced in the skin of intrinsically aged A1 guinea pigs in the absence of UV irradiation, a process that differs from that elicited by UV irradiation.     

Species Differences in the Brain Regional Distribution of Receptor Binding for Thyrotropin-Releasing Hormone

Abstract: A survey of the regional distribution of binding of 1 nM [³H](3-MeHis²)thyrotropin-releasing hormone ([³H]MeTRH) to TRH receptors in the brains of eight mammalian species revealed major species differences in both the absolute and relative values of TRH receptor binding in different brain regions. Several brain regions exhibited binding equal to or exceeding that in the anterior pituitary gland of the same species, including the amygdaia in the guinea pig and rat, the hypothalamus in the guinea pig, the nucleus accumbens in the rabbit, and all these and other regions in the cat and dog, for which pituitary binding was exceptionally low. Species could be divided into two groups according to which brain region appeared highest in binding: rabbits, sheep, and cattle had highest binding in the nucleus accumbens/septal area, whereas guinea pigs, rats, dogs, cats, and pigs had highest binding in the amygdala/temporal cortex area. The nucleus accumbens consistently exceeded the caudate-putamen in receptor binding. For most brain regions, rabbits, rodents, and sheep tended to be higher than carnivores, cattle, or pigs. Further regions that exhibited appreciable binding in most species included the olfactory bulb and tubercle, hippocampus, and various cortical and brain stem areas. In fact, essentially all brain regions appeared to have detectable levels of TRH receptors in at least some species, but no rat peripheral tissues have yet shown detectable receptor binding. The species differences appeared to reflect largely if not entirely differences in receptor density, although this was not tested in every species.     

The organizational characteristics of the APUD system in mammalian lungs at different stages of ontogeny]

The organization peculiarities of APUD-system in the lungs of rabbits, rats and guinea pigs has been studied. The endocrine system in the lungs of rabbits in pre- and postnatal ontogenesis is presented by the adipocytes and neuroepithelial bodies (NEB) containing a considerable number of monoamines. The number of argyrophil adipocytes and NEBs in the lungs of 21 and more day-old adult rats seem to be less than in fetuses and newborns. Monoamines are not revealed in the endocrine rat lung structures by means of the glyoxylic acid. In the lungs of guinea pigs the single argyrophil adipocytes and NEBs are determined in the gestation period.