Hippocampus is a brain structure containing vasopressin (AVP) fibers and specific binding sites for this peptide. There is growing evidence that AVP and its metabolites participate in glutamate-mediated plasticity of the hippocampus. The aim of the present study was to evaluate the influence of NMDA on AVP release in the rabbit hippocampus. Caudate nucleus was chosen as the reference structure. The mentioned brain structures were simultaneously microdialyzed with 0.9 % NaCl solution. AVP was determined in the outflowing fluid by radioimmunoassay. The mean basal AVP content in the fluid outflowing from the hippocampus was significantly greater than that from the caudate nucleus. The addition of K+ into the fluid perfusing the probes implanted into the hippocampus and caudate nucleus significantly increased AVP release into the extracellular fluid of both brain structures. NMDA applied into the mentioned brain structures increased AVP release only from the hippocampus but not from the caudate nucleus. Our findings indicate a role which NMDA receptors play in AVP release into the extracellular fluid of the hippocampus., M. Orłowska-Majdak, W. Z. Traczyk, D. Szymański., and Obsahuje bibliografii
The use of reversible lesion techniques in memory research was pioneered in the laboratory of Jan Bureš and Olga Burešova. We use the occasion of Jan’s 75th birthday to briefly review the experimental utility of this approach. Two experiments from our current research are reported in which reversible lesioning methods are used to ask otherwise experimentally untenable questions about memory retrieval. The first experiment used intra-hippocampal injections of tetrodotoxin to temporarily inactivate the hippocampus during retrieval of a well-learned place avoidance navigation memory. This revealed that the hippocampus is necessary for place avoidance retrieval but that the extinction of place avoidance can occur independently of retrieving the memory and intact hippocampal function. The second experiment used KCl-induced cortical spreading depression in an interhippocampal transfer paradigm to demonstrate that a Y-maze memory that is learned by only one cortical hemisphere can be made to transfer to the other hemisphere by forcing the rat to swim, a unique stressful experience that occurred in a different apparatus, different behavioral context, and involved different behaviors than the Y-maze training. This demonstrates, we believe for the first time behaviorally, that memories can be activated outside of the behavioral context of their acquisition and expression in rats., K. Ježek, M. Wesierska, A. A. Fenton., and Obsahuje bibliografii
The aim of this study was to determine the relative contribution of nitric oxide (NO), endothelium-derived hyperpolarizing factor (EDHF) and prostanoids in histamine-induced relaxation of isolated pulmonary artery from normotensive and hypertensive rats. The hypertension was induced by oral administration of NO synthase inhibitor NG-nitro-L-arginine methylester (L-NAME, 50 mg/kg/day) to normotensive rats for 8 weeks. In phenylephrine-precontracted arterial rings the histamine-induced relaxation was significantly reduced in L-NAME-treated rats compared to the controls. Indomethacin (cyclooxygenase inhibitor) and glibenclamide (ATP-sensitive K+-channel blocker) did not inhibit the relaxation response in either control or hypertensive rats. On the other hand, tetraethylammonium (TEA), a K+-channel blocker with a broad specificity, significantly reduced histamine-induced relaxation in the pulmonary artery from both groups examined. The TEA-resistant relaxation was completely abolished by additional administration of L-NAME to the incubation medium. The results indicate that histamine-induced relaxation of the pulmonary artery in both normotensive and hypertensive rats is mediated mainly by nitric oxide, whereas EDHF seems to play a minor role., J. Török., and Obsahuje bibliografii
Bretschneider (histidine-tryptophan-ketoglutarate) solution with its high histidine concentration (198 mM) is one of many cardioplegic solutions, which are routinely used for cardiac arrest. The aim of this study was to evaluate the physiological biochemical degradation of administered histidine to histamine and its major urinary metabolite N-methylimidazole acetic acid. A total number of thirteen consecutive patients scheduled for elective isolated coronary artery bypass grafting with cardiopulmonary bypass were enrolled in the prospective observational designed study at the Department of Thoracic and Cardiovascular Surgery between 04/2016 and 06/2016. Patients received 1.7 l Bretschneider solution on average. Before and at the end of operation as well as in the postoperative course, urine samples gathered from the urinary catheter bag were analyzed. During the operative period, urinary histidine concentration significantly increased from 29 μmol/mmol creatinine to 9,609 μmol/mmol creatinine. Postoperatively, histidine excretion reduced while histamine as well as N-methylimidazole acetic acid excretion rose significantly. Patients showed elevated levels of histidine, histamine as well as N-methylimidazole acetic acid in urine, but no unmanageable hemodynamic instability possibly arising from the histamine’s biological properties. Chemically modified histidine might reduce uptake and metabolization while maintaining the advantages of buffer capacity., J. K. Teloh, L. Ansorge, M. Petersen, E. Demircioglu, I. N. Waack, S. Brauckmann, H. Jakob, D.-S. Dohle., and Seznam literatury
Histochemical studies of enzyme activities and structural elements in Gyrodactylus derjavini Mikailov, 1975 parasitizing fins of Oncorhynchus mykiss Walbaum were conducted. Marked activities of non-specific esterase, acid phosphatase, alkaline phosphatase and amino-peptidase were found in the intestinal caeca of the parasite. A strong activity of acetylcholinesterase was seen in the nervous system. Extraintestinal non-specific and eserine-sulphate resistant esterase was localized in the distal part of the hamulus sheath. Activities of peroxidase and glucuronidase were not detected. In the embryo, developing hamuli were enclosed in a sheath rich in phospholipids. Deposits of neutral lipids were sparse. The fully developed ventral and dorsal hamulus bars stained strongly for calcium. Lectin binding assays showed a mannose rich region in the cephalic duct openings, strong reactions for galactose in the glycocalyx whereas reactions for lactose were weak. These findings arc discussed with respect to the parasite-host relationship.
During an ongoing systematic survey on species diversity of myxozoans parasitising allogynogenetic gibel carp Carassius auratus gibelio (Bloch) in China, plasmodia were detected in the fins, lip, jaw, gill chamber, gill arches, operculum and oral cavity of infected fish. Combining the morphological and molecular data, the present species was identified as Myxobolus turpisrotundus Zhang, Wang, Li et Gong, 2010. Histopathological examination revealed that despite infecting different organs, M. turpisrotundus always occurred in dermis, demonstrating its affinity to this tissue. Histopathological effect of M. turpisrotundus on the host is relatively mild except parasites in the gill arches producing compression of the adipose tissue and heavy adductor muscles deformation with lymphohistiocytic infiltrates. In addition, the plasmodia in different sites were with the same complex structure arrangement: cup-like cells with unknown derivation, a thin collagenous fibril layer, areolar connective tissue, basement membrane and host epithelial cell. Ultrastructural analysis showed that the parasite has monosporic pansporoblast and sporogenesis followed the usual pattern of most of the myxosporeans., Qingxiang Guo, Yanhua Zhai, Zemao Gu, Yang Liu., and Obsahuje bibliografii
Postlarvae of the cestode Hepatoxylon trichiuri (Holten, 1802) were found attached to the surface of viscera of Prionace glauca (Linnaeus, 1758) taken from Atlantic coastal waters off the south coast of Massachusetts, USA. Gross anatomy of the attachment site shows a quadripartite rim surrounding a deep pit with holes corresponding to the penetration site of each tentacle. Hyperplasia of the liver capsule into outgrowths at the attachment site conform to the attachment of the bothridia. The cu-boidal epithelium of the liver capsule became columnar forming papillary outgrowths, with a dense fibrotic reaction beneath the attachment site and infiltration by leukocytes and pigment containing granulocytic cells. Blood sinusoids beneath the attachment site are greatly enlarged. Postlarvae attached to the surface of the epigonal organs of three blue sharks were not accompanied by reactions. SEM examination of the scolex of H. trichiuri postlarvae revealed fused pairs of bothridia within infolded muscular lateral rims, porose tegument devoid of microtriches and a bilateral plane of symmetry in the tentacular armature.
The microsporidian Kabatana arthuri (Lom, Dyková et Shaharom, 1990) induced severe regressive changes in trunk muscles of Pangasius sutchi (Fowler) from Thailand. Necrotic changes developed in muscle fibres around the developmental stages and on the periphery of giant aggregates of spores. The main feature of the host defence reaction was the phagocytic activity of macrophages. Inflammatory reaction was only exceptionally observed. Spore-laden macrophages were found in various tissues and organs; their infiltration in epidermis including its outermost layers may effectively enhance the spread of infection while the hosts still live.
Physaloptera brevivaginata has been found parasitising the stomach of two species of bats of the family Vesperti-lionidae, Myotis myotis and Myotis blythii, in Spain. A comparative study of the prevalences and mean intensities of parasitism by this physalopterid revealed no statistically significant differences between the two hosts. Likewise, no relationship was found between parasite intensity and host body weight. The histopathological study of the stomach lesion revealed destruction of the mucosa, with degeneration of the gastric glands, loss of the muscularis mucosae and focal necrosis at the points where the cephalic extremities of both sexes of this nematode attach to the mucosa. The present paper is the first study of gastric pathology caused by an adult physalopterid in bats.