Comparison of brain ribonucleases of rabbit, guinea pig, rat, mouse and gerbil

The brain ribonucleases of rabbit, guinea pig, rat, mouse and gerbil were investigated by histochemical and biochemical methods. For the localization, the ribonucleases were electrophoretically transferred from cryostat sections to polyacrylamide gels. Elevated ribonuclease activities were found in the cortex, the basal ganglia, the hippocampal formation and the ventricles, whereas the corpus callosum and the internal capsule exhibited lower activities. The total RNA degrading activities of the brain extracts of the different species varied in a wide range. However, a pre-requisite for the measurement of acid soluble degradation products in the test system was the inactivation of endogeneous ribonuclease inhibitors, present in all extracts. Molecular weight analysis by means of SDS-polyacrylamide gel electrophoresis revealed a characteristic set of ribonucleases for each species, consisting of enzymes with different pH-optima.     

Comparison of brain ribonucleases of rabbit,guinea pig,rat, mouse and gerbil

Summary The brain ribonucleases of rabbit, guinea pig, rat, mouse and gerbil were investigated by histochemical and biochemical methods. For the localization, the ribonucleases were electrophoretically transferred from cryostat sections to polyacrylamide gels. Elevated ribonuclease activities were found in the cortex, the basal ganglia, the hippocampal formation and the ventricles, whereas the corpus callosum and the internal capsule exhibited lower activities. The total RNA degrading activities of the brain extracts of the different species varied in a wide range. However, a pre-requisite for the measurement of acid soluble degradation products in the test system was the inactivation of endogencous ribonuclease inhibitors, present in all extracts. Molecular weight analysis by means of SDS-polyacrylamide gel electrophoresis revealed a characteristic set of ribonucleases for each species, consisting of enzymes with different pH-optima.Dedicated to Professor Dr. T.H. Schiebler on the occasion of his 65th birthday     

Beta-endorphin-like and adrenocorticotropin-like materials in heart tissues of the rat, gerbil, hamster and guinea pig

1. Heart tissues of several rodent species including the rat, gerbil (Meriones unguiculatus), hamster (Mesocricetus auratus) and guinea pig (Cavia porcellus) were extracted with an acetone-water-HCl mixture. An acid acetone powder was obtained by adding a copious volume of acetone to the extract. 2. Rat heart acid acetone powder was subjected to ion exchange chromatography on CM-cellulose. Gerbil heart acid acetone powder was subjected to salt fractionation, gel filtration on Sephadex G-10 and then ion exchange chromatography on CM-cellulose. Hamster and guinea pig heart acid acetone powders were subjected to gel filtration on Sephadex G-25. 3. The fractions were assayed for the ability to stimulate corticosterone production in isolated rat adrenal decapsular (zona fasciculata, zona reticularis and medulla) cells, to displace D-ala2-D-leu5-(tyrosyl-3,5-3H) enkephalin from binding to rat brain membranes, and to inhibit 125I-human beta-endorphin from binding to its antibodies. 4. The widespread occurrence of beta-endorphin-like immunoreactivity among the rat heart CM-cellulose fractions may reflect different species of beta-endorphin. The fraction with the highest beta-endorphin-like immunoreactivity and opiate receptor binding activity was strongly adsorbed on CM-cellulose. 5. In hamster and guinea pig hearts, beta-endorphin-like immunoreactivity and opiate receptor binding activity were distributed among high molecular weight and low molecular weight fractions. 6. In gerbil hearts, opiate receptor binding activity was present in fractions unretarded on Sephadex G-10 (i.e. with a molecular weight greater than 700) as well as in the retarded fractions (i.e. with a molecular weight smaller than 700).(ABSTRACT TRUNCATED AT 250 WORDS)     

The production and storage of Nerve Growth Factor in vivo by tissues of the mouse,rat, guinea pig,hamster, and gerbil

The Nerve Growth Factor (NGF) content in vivo of tissues from the mouse and rat at various stages of development from 3 days embryonic gestation to the attainment of full maturity has been determined using the standard biological assay. A less extensive survey has also been made of tissues from the guinea pig, hamster, and gerbil. With the exception of the well-documented high levels of NGF in the mouse submaxillary glands, none of the organs examined contained detectable NGF. These results, which are consistent with those previously reported using the biological assay, stand in contrast to the high levels of NGF detected in virtually all tissues by some published radioimmunoassays. It is likely that the discrepancies are due to the use in the radioimmunoassays of antisera containing antibodies to proteins other than NGF, and to the inability of one-site radioimmunoassays to distinguish between the presence of NGF and that of agents capable of binding NGF. The apparent lack of widespread NGF production in vivo contrasts with the ability of many tissues to synthesize the protein in vitro. This may imply that physiologically significant levels of NGF are below the limits of sensitivity of the assay systems presently available, that NGF synthesis in vivo occurs only during a very restricted period of development, or that the presence of a normal innervation pattern influences NGF production.     

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.     

Kappa-opioid receptor in the rodent hippocampus: a comparative immunocytochemical study in the rat,guinea pig,hamster and gerbil

Pre-embedding light microscopic immunocytochemistry, using a monoclonal antibody (mAb-KA8) raised against a frog brain kappa receptor preparation, recognising selectively the kappa-opioid receptor, was used for studying the occurrence, distribution, and species-specificity of the kappa-opioid receptor in the hippocampal formation of four rodent species (rat, guinea pig, hamster and gerbil). MAb-KA8 immunoreactivity was detectable in the rat, hamster and gerbil hippocampus, however the distribution of the labelled structures was heterogeneous. In the rat and hamster the hilus of dentate gyrus and the stratum oriens of the CA1 area contained immunoreactive cell bodies and proximal dendrites. In the gerbil mAb-KA8 immunopositive cell bodies were recognisable in the stratum radiatum of the CA1 and CA3 areas and in the subiculum. In the hamster varicose axon-like elements were also detected in the CA3 pyramidal layer. With the mAb-KA8 antibody there was no detectable kappa opioid receptor labelling in the hippocampus of the guinea pig. The results confirm the high degree of species-specific heterogeneity characterising the distribution of opioid peptides and their receptors in the hippocampal formation. The receptor was found in most cases postsynaptically, however in the hamster the immunopositive axons may refer to a presynaptic localisation.     

Distribution of serotonin immunoreactive neurons in the brainstem of the hamster, guinea pig, rabbit, and rat

Immunohistochemical techniques were employed to study the distribution of serotonin (5-HT) immunoreactive neurons in the brainstem of the hamster, guinea pig, rabbit and rat. 5-HT neurons were principally found to be concentrated in the midline raphe nuclei, particularly, the raphe pallidus, raphe obscurus, raphe magnus, raphe median, raphe pontis and raphe dorsalis nuclei. Characteristically, these cell bodies are displayed in bands or wing-like patterns which extend laterally from the raphe into reticular formations. The formations often appear to blend with the catecholamine system. They are particularly evident in the brainstems of the rabbit and hamster which contain wider and more lateral extensions of the serotonergic (5-HT) neurons than those observed in the brainstems of the rat and guinea pig. The widespread distribution of 5-HT immunoreacted cell bodies in the brainstem shows that there are significant prospects of 5-HT in neuronal activities.     

A comparative study of the conversion of 7-hydroxycholesterol in rabbit,guinea pig,rat, hamster,and chicken

The metabolism of epimeric 7-hydroxycholesterol was studied in vitro. 7Alpha-hydroxycholesterol or 7beta-hydroxycholesterol were incubated with rabbit, guinea pig, rat, hamster, and chicken microsomal suspensions and then extracted and analyzed using high-performance liquid chromatography (HPLC). 7Alpha-hydroxy-4-cholesten-3-one was the main product from 7alpha-hydroxycholesterol in the rabbit, guinea pig, and rat. A considerable amount of 7-ketocholesterol was also produced in the hamster and chicken. In all vertebrates, 7beta-hydroxycholesterol was converted only to 7-ketocholesterol in all vertebrates. 7Beta-hydroxy-4-cholesten-3-one was not detected. Reduction of 7-ketocholesterol was also studied in the rat and hamster. Whereas 7-ketocholesterol was converted to 7beta-hydroxycholesterol in the rat, it was converted to both 7alpha- and 7beta-hydroxycholesterol in the hamster. These results suggest that 7alpha-hydroxycholesterol is converted not only to 7alpha-hydroxy-4-cholesten-3-one but also to 7-ketocholesterol in the hamster and chicken. 7Beta-hydroxycholesterol was converted to 7-ketocholesterol in all vertebrates tested. The interconversion between 7alpha- and 7beta-hydroxycholesterol via 7-ketocholesterol was observed in the hamster in this in vitro study.     

Expression of P2X5 receptors in the rat, cat, mouse and guinea pig dorsal root ganglion

P2X receptors are ATP-gated cationic channels composed of seven cloned subunits (P2X_{1 –7}). P2X₃ homomultimer and P2X_2/3 heteromultimer receptors expressed by primary afferent dorsal root ganglion (DRG) neurons are involved in pain processing. The aim of the study was to investigate the expression of the P2X₅ receptor subunit in DRG in different species including mouse, rat, cat and guinea pig. Immunohistochemistry showed that P2X₅ receptors exhibited low levels of immunostaining in rat DRG, but high levels in mouse and guinea pig. Only a few neurons were immunoreactive for P2X₅ receptors in cat. In mouse DRG, the P2X₅ receptor was expressed largely by medium-diameter neurons (42.9 %), less in small (29.3 %) and large (27.8 %) neurons. In contrast, in the guinea pig DRG, P2X₅ receptor expression was greatest in small-diameter (42.6 %), less in medium- (36.3 %) and large-diameter (21.1 %) neurons. Colocalization experiments revealed that, in mouse DRG, 65.5, 10.9 and 27.1 % of P2X₅ receptors were immunoreactive for NF-200, CGRP and calbindin, while only a few P2X₅-immunoreactive (IR) neurons were coexpressed with IB4 or with NOS. In guinea pig DRG, a total of 60.5 and 40.5 % of P2X₅-IR neurons were coexpressed with IB4 or with CGRP, while 20.3 and 24.5 % of P2X₅ receptors were coexpressed with NF-200 or with NOS. Only a few P2X₅-IR neurons were coexpressed with calbindin in guinea pig DRG. It will be of great interest to clarify the relative physiological and pathophysiological roles of P2X₅ receptors.     

Ultrastructural analysis of the effect of ethane dimethanesulphonate on the testis of the rat,guinea pig,hamster and mouse

Summary The morphological response of the testis of rats, guinea pigs, Syrian hamsters and mice to treatment with the cytotoxin ethane dimethanesulphonate was examined using light and electron microscopy. One to two days after a single administration of ethane dimethanesulphonate to adult rats, guinea pigs, and hamsters, the Leydig cells showed marked ultrastructural alterations suggestive of degeneration and cell death. The former alterations included karyopyknosis, cytoplasmic vesiculation and accumulation of lipid inclusions and large lipofuscin bodies. Fragments of necrotic Leydig cells were often engulfed by the interstitial tissue macrophages. The morphology of the seminiferous epithelium of these three species was unchanged from the morphology observed in vehicle-injected control animals. In contrast, multiple injections of ethane dimethanesulphonate given to mice produced no ultrastructural alterations to Leydig cells yet the seminiferous epithelium exhibited disruption of spermatogenesis. Although the Leydig cells of the mouse appear resistant to ethane dimethanesulphonate, this agent exerts a selective cytotoxic action upon Leydig cells of the rat, guinea pig and hamster thus identifying ethane dimethanesulphonate as a useful chemical for future endocrine and physiological studies of testicular function in three common laboratory species.