Cold-resistant changes in heartbeat of the Japanese spiny lobster

Heartbeat in Panulirus japonicus acclimated to 20°C is often augmented during cooling to 15^oC. Augmented contractions of the heart coincided with increasing amplitude of electrocardiogram. In cold saline, a pericardial hormone serotonin (10⁻⁷ M) increased both the amplitude and duration of the heartbeat while another hormone octopamine (10⁻⁶ M) slightly relieved the cold depression of heart rate despite a smaller increase in beat amplitude. In contrast, the application of the cold saline containing F1 (a FMRFamide-related peptide of pericardial hormones, 10⁻⁹ M) maintained the rate and amplitude of the heartbeat around the control level during cold exposure. This suggests that in the presence of F1, the lobster heart becomes cold resistant clearly. We previously reported that the pericardial organs of spiny lobsters are activated by a small fall in body temperature. The ligamental nerves, extensions of the pericardial organs, terminate in the heart beside the ostia and their ends remain in the isolated hearts. Therefore, the ligamental nerve ends might release their hormones into the ventricle with the fall in temperature even in the isolated hearts.     

Mass spectrometric characterization and physiological actions of VPNDWAHFRGSWamide, a novel B type allatostatin in the crab, Cancer borealis

The neural networks in the crustacean stomatogastric ganglion are modulated by neuroactive substances released locally into the neuropil of the stomatogastric ganglion and by circulating hormones released by neuroendocrine structures including the pericardial organs. Using nanoscale liquid chromatography coupled to electrospray ionization quadrupole-time-of-flight mass spectrometry, we have identified and sequenced a novel B type allatostatin (CbAST-B1), VPNDWAHFRGSWamide, present in the pericardial organs of the crabs, Cancer borealis, and Cancer productus. We describe the physiological actions of CbAST-B1 on the pyloric rhythm of the stomatogastric ganglion of the crab, Cancer borealis. CbAST-B1 reduces the pyloric network frequency in a dose-dependent manner. The effect of bath-applied CbAST-B1 depends on the preceding physiological state of the preparation. Surprisingly, despite marked amino-acid sequence dissimilarity between the novel CbAST-B1 and the A type allatostatin family of peptides (AST-A), the physiological effects of CbAST-B1 are similar to those of AST-A.     

PART I. The Nature and Localization of Neuroseoretory Substances Isolation and Identification of Cardio-Excitor Hormone from the Pericardial Organs of Cancer borealis

Extracts of the neurohemal pericardial organs from Cancer borealishave a cardio-excitor activity when tested on the isolated,perfused heart. Analysis of the extract indicates that thereare two active peptides, similar in size and amino acid composition.The procedure for isolation of these peptides is presented,as well as a discussion of the proposed role of indolic substancesas cardio-excitor agents.     

Studies on the crustacean cardiac ganglion

1. An overview of studies on the decapod crustacean cardiac ganglion is given emphasizing contributions to questions of general interest in cellular neurophysiology. 2. John Welsh, in 1951, introduced this 9-celled, semi-autonomous ganglion as a preparation offering physiologists unique experimental possibilities. 3. It exhibits remarkable reliability and stability in rhythmic pattern generation. The neurons show endogenous burst-forming capability mediated by "driver potentials". 4. These regenerative, Ca-mediated potentials are restricted to the soma, while impulse-generating membrane is segregated to the distal axon. 5. Thus, voltage-clamp analysis of the ionic currents underlying the burst-forming potentials is possible by isolating the soma with a ligature. 6. The isolated ganglion is spontaneously active, but the normal mechanism of pacemaking remains to be clarified, including the possible contribution of stretch-sensitive dendrites. 7. The activity of the ganglion is subject to modulation by neurohumors. These include the transmitter at intraganglionic synapses, transmitters of the pair of inhibitory and the two pairs of acceleratory fibers, and neurohormones released from the pericardial organs. The transmitters are not established. 8. Effects on the ganglion of substances isolated from the pericardial organs have been described. 9. These include 5-hydroxytryptamine, dopamine, octopamine, and two peptides. 10. One of these, proctolin, produces a long-lasting sequence of effects. 11. The work continues to raise new questions for which the ganglion offers excellent research material.     

异齿裂腹鱼仔鱼的黑色素分布

本文运用组织学方法对异齿裂腹鱼仔鱼发育过程中除眼睛以外的黑色素分布进行研究。结果表明: 异齿裂腹鱼孵化出膜后,黑色素在各个组织器官的出现顺序为: 脑颅外膜→围心腔、背部皮肤→腹腔内膜、脊髓腔。其中,出膜5 d时脑颅外膜处出现黑色素;7 d时围心腔和背部皮肤出现黑色素;10 d时腹腔内膜、脊髓腔出现黑色素。异齿裂腹鱼出膜10 d后,其皮肤和内脏器官(脑颅、围心腔、腹腔内膜、脊髓腔)均具有黑色素,且主要分布在背侧。黑色素在异齿裂腹鱼仔鱼发育过程中的出现时序和分布规律可能与其所处的强紫外辐射环境有关。本研究可为研究鱼类黑色素的紫外防护机制提供参考,并为今后高原鱼类仔鱼的培育条件优化提供理论支撑。     

Ultrastructural study of the pericardial organ-anterior ramifications complex neurosecretory terminals

Summary The pericardial organ-anterior ramifications complexes of Uca pugilator and Callinectus sapidus were studied by transmission electron microscopy. Five morphologically distinguishable groups of granules and two groups of vesicles were identified. These granules and vesicles are present in approximately the same proportions in the pericardial organs and anterior ramifications of both species. Two of the granule groups are never mixed in the same axon terminals and are believed to represent different hormone-protein complexes. The remaining granule and vesicle groups are believed to be products of neurosecretory hormone release. Evidence that at least some of these granules and vesicles arise from intraaxonal release of neurosecretory material is presented.This work was supported by USPHS-NIH Training Grant GM-00669 and by the University of Texas Institutional Grant No. 5 SO 1 RR 05426-11.     

Occurrence and parasite fauna of Dressena bugensis in the Rybinsk reservoir

The zebra mussel Dreissena bugensis (Andrusov), a representative of mollusc fauna in the Dnieper-Bug estuary, have been found for the first time in the Rybinsk reservoir (the Volga reach, Shumorovka River). In pericardial and mantle cavities and inner organs of molluscs the following parsites have been found: Aspidogaster limacoides, Caspiobdella fadejevi, Helobdella stagnalis, eggs of the water mites of the genus Unionicola, and representatives of nonspecific saprotrophic fungi of the genus Acremonium. It is shown that composition of parasites and free-living organisms in D. bugensis is similar to that in D. polymorpha.     

The morphology of the axial complex and associated structures in Asterozoa (Asteroidea,Echinoidea, Ophiuroidea)

The representatives of Asterozoa (Asteroidea, Echinoidea, and Ophiuroidea) have a similar structural plan of the axial complex with minor differences within each class; this structural scheme substantially differs from that in Crinozoa and Holothurozoa. The axial complex consists of the coelomic organs and the haemocoel (blood) structures, which are morphologically and functionally integral. The coelomic organs are the stone canal, axial coelom, perihaemal coeloms (axocoel perihaemal ring and somatocoel perihaemal ring), water ring, and pericardial and genital coeloms. These organs are closely associated with the epigastric and hypogastric coeloms and with the perioral coelomic ring. The haemocoel structures of the axial complex include the oral haemal ring, heart, axial organ, genital haemal ring, and gastric haemal ring. The epineural canals of echinoids and ophiuroids are of a noncoelomic nature. They are formed by the invagination of the ectoneural cord and closing of the epidermis above it. The possible functions of the axial complex in Asterozoa are blood circulation and excretion.     

Diagnostic utility of CYFRA 21-1 and CEA assays in pericardial fluid for the recognition of neoplastic pericarditis

A positive cytology result in pericardial fluid is the gold standard for recognition of malignant pericardial effusion. Unfortunately, in 30-50% of patients with malignant pericardial effusion cytological examination of the pericardial fluid is negative. Tumor marker assessment in pericardial fluid may help to recognize malignant pericardial effusion. The aim of our study was to estimate the value of CYFRA 21-1 and CEA measurement in pericardial fluid for the recognition of malignant pericardial effusion. To our knowledge this is the first study on CYFRA 21-1 assessment in pericardial effusion. The examined group consisted of 50 patients with malignant pericardial effusion and 34 patients with non-malignant pericardial effusion. Median CEA concentrations in malignant pericardial effusion and non-malignant pericardial effusion were 80 ng/mL (0-317) and 0.5 ng/mL (0-18.4), respectively (p<0.001). Median CYFRA 21-1 concentrations in malignant pericardial effusion and non-malignant pericardial effusion were 260 ng/mL (5.3-10080) and 22.4 ng/mL (1.87-317.6), respectively (p<0.001). The optimal cutoff value for CYFRA 21-1 in pericardial effusion was 100 ng/mL. CYFRA 21-1 >100 ng/mL or CEA >5 ng/mL were found in 14/15 patients with malignant pericardial effusion and negative pericardial fluid cytology. We therefore strongly recommend the use of CYFRA 21-1 and/or CEA in addition to pericardial fluid cytology for the recognition of malignant pericardial effusion.     

Pericardial fat amount is an independent risk factor of coronary artery stenosis assessed by multidetector-row computed tomography: the Korean Atherosclerosis Study 2

Pericardial fat surrounding the heart and coronary arteries might aggravate vessel wall inflammation and stimulate the progression of coronary atherosclerosis. However, there has been little comprehensive evaluation of the effects of pericardial fat on coronary artery disease (CAD). We investigated the relationship between pericardial fat volume and the severity of coronary artery stenosis assessed by computed tomography and angiography among patients with suspected CAD. Participants from the cohort of the Korean Atherosclerosis Study 2 (n = 402, mean age of 54 years, 57.0% men) underwent 64-slice multidetector-row computed tomography (MDCT) to assess pericardial fat amount, coronary artery calcium score (CACS), severity of coronary artery stenosis, and plaque characteristics. Patients with atherosclerotic lesion had significantly larger volume of pericardial fat than patients without atherosclerosis (308 ± 96 cm(3) vs. 251 ± 93 cm(3); P < 0.01). In a multivariate regression analysis adjusting for age, gender and BMI, subjects with more pericardial fat had a higher risk for significant (>50%) stenosed coronary vessels (odds ratio (OR) = 1.012; 95% confidence interval (CI) 1.001-1.030; P = 0.017). This association remained after adjusting for hypertension, diabetes, smoking status, and lipid profiles (OR = 1.007; 95% CI 1.001-1.014; P = 0.042). In conclusion, an increased pericardial fat volume was an independent risk factor for stenotic CAD and could be helpful in assessing subclinical CADs.     

Identification and immunocytochemical localization of proctolin in pericardial organs of the shore crab, Carcinus maenas

The occurrence of proctolin (Arg-Tyr-Leu-Pro-Thr) in crab neurohemal pericardial organs (POs) has been demonstrated by isolation of the pentapeptide by HPLC and manual microsequencing according to the DABITC-PITC double coupling technique. From one pair of POs approximately 5.4 pmol were obtained (= 45 pmol/mg protein). Immunocytochemically, an extensive system of positive structures was found in both whole mount preparations and semithin sections, consisting of numerous varicose fibres of varying diameter and many knoblike neurosecretory terminals abutting upon the epineurium of the PO trunks. The relatively high concentration in the POs as well as the pattern of proctolin-positive fibres and terminals clearly suggest a neurohormonal role of the pentapeptide in decapod crustaceans.     

Distribution of a novel cardioactive neuropeptide (CCAP) in the nervous system of the shore crab Carcinus maenas

A radioimmunoassay (RIA) for the recently discovered crustacean cardioactive peptide (CCAP) has been developed and used to determine contents of CCAP in different parts of the nervous system of the shore crab Carcinus maenas. Immunoreactive material was detected throughout the nervous system. In contrast to the main ganglia which contained low levels of approximately 1.4 pmol CCAP/mg protein (brain and thoracic ganglion), a high concentration was found in a neurohemal structure, the pericardial organs (PO) (868 pmol/mg protein). A predominantly neurohormonal role of CCAP thus suggested is further supported by in vitro release studies. Incubation of POs in high (K+) saline showed that CCAP is secretable in considerable amounts by a Ca++-dependent release mechanism.     

细尾高原鳅和东方高原鳅不同组织器官黑色素的分布和比较

采用组织学方法比较研究细尾高原鳅和东方高原鳅组织器官的黑色素分布特征。结果显示: 两种高原鳅头部皮肤、背部皮肤、体侧皮肤、腹膜肾脏层、脊髓腔壁层、腹膜壁层、围心腔壁层、脑颅腔壁层和眼睛均分布有黑色素;腹部皮肤、肝脏浆膜、脾脏被膜和性腺被膜未发现黑色素。皮肤中黑色素分布在真皮层和皮下组织,其他组织器官中黑色素分布在内膜层或壁层。黑色素主要分布在背侧,体侧则分布稀疏,呈现对称分布。背部和体侧皮肤有斑块处较无斑块处黑色素数量多,分布密集;无斑块处仅是部分聚集,或形成间断分布的黑色素块。同一种高原鳅不同组织器官黑色素分布不同,分布面积百分比和黑色素层厚度有显著性差异,但两种高原鳅同一组织器官黑色素分布特征相似。两种高原鳅组织器官中黑色素的分布与其接受的紫外辐射强度有关,是对高原强紫外辐射环境的适应。     

细尾高原鳅和东方高原鳅不同组织器官黑色素的分布和比较

采用组织学方法比较研究细尾高原鳅和东方高原鳅组织器官的黑色素分布特征。结果显示: 两种高原鳅头部皮肤、背部皮肤、体侧皮肤、腹膜肾脏层、脊髓腔壁层、腹膜壁层、围心腔壁层、脑颅腔壁层和眼睛均分布有黑色素;腹部皮肤、肝脏浆膜、脾脏被膜和性腺被膜未发现黑色素。皮肤中黑色素分布在真皮层和皮下组织,其他组织器官中黑色素分布在内膜层或壁层。黑色素主要分布在背侧,体侧则分布稀疏,呈现对称分布。背部和体侧皮肤有斑块处较无斑块处黑色素数量多,分布密集;无斑块处仅是部分聚集,或形成间断分布的黑色素块。同一种高原鳅不同组织器官黑色素分布不同,分布面积百分比和黑色素层厚度有显著性差异,但两种高原鳅同一组织器官黑色素分布特征相似。两种高原鳅组织器官中黑色素的分布与其接受的紫外辐射强度有关,是对高原强紫外辐射环境的适应。     

Peptidergic modulation of cardiovascular dynamics in the Dungeness crab,Cancer magister

Decapod crustacean pericardial organs contain extensive neurohormonal reserves which can be released directly into the haemolymph to act as physiological modulators. The present paper concerns the in vivo effects of two pericardial peptides, proctolin and crustacean cardioactive peptide, on cardiovascular dynamics in the crab Cancer magister. Infusion of proctolin into the pericardial sinus caused a slight decrease in heart rate concurrent with a large increase in cardiac stroke volume. It decreased haemolymph flow anteriorly through the paired anterolateral arteries and increased flow posteriorly and ventrally through the posterior aorta and sternal artery, respectively. The threshold for responses occurred at circulating concentrations of 10^-9 mol·l^-1, and haemolymph flows remained elevated for up to 30 min after peptide infusion. The effects of crustacean cardioactive peptide were less dramatic. Heart rate was not affected but a significant increase in stroke volume was observed. Crustacean cardioactive peptide increased haemolymph flow through the anterolateral arteries and increased scaphognathite rate. The threshold for crustacean cardioactive peptide activity was higher than for proctolin (10^-7 mol·l^-1 and 10^-6 mol·l^-1) but the responses to crustacean cardioactive peptide were of longer duration. The effects of proctolin on regional haemeolymph distribution in Cancer magister closely resemble the cardiovascular responses of this species when exposed to hypoxic conditions. These peptides may be implicated as cardiovascular regulators during environmental perturbations.