Dorsal and ventral medullary catecholamine cell groups contribute differentially to systemic interleukin-1beta-induced hypothalamic pituitary adrenal axis responses

Medial parvocellular paraventricular corticotropin-releasing hormone (mPVN CRH) cells are critical in generating hypothalamic-pituitary-adrenal (HPA) axis responses to systemic interleukin-1beta (IL-1beta). However, although it is understood that catecholamine inputs are important in initiating mPVN CRH cell responses to IL-1beta, the contributions of distinct brainstem catecholamine cell groups are not known. We examined the role of nucleus tractus solitarius (NTS) and ventrolateral medulla (VLM) catecholamine cells in the activation of mPVN CRH, hypothalamic oxytocin (OT) and central amygdala cells in response to IL-1beta (1 microg/kg, i.a.). Immunolabelling for the expression of c-fos was used as a marker of neuronal activation in combination with appropriate cytoplasmic phenotypic markers. First we confirmed that PVN 6-hydroxydopamine lesions, which selectively depleted catecholaminergic terminals, significantly reduced IL-1beta-induced mPVN CRH cell activation. The contribution of VLM (A1/C1 cells) versus NTS (A2 cells) catecholamine cells to mPVN CRH cell responses was then examined by placing ibotenic acid lesions in either the VLM or NTS. The precise positioning of these lesions was guided by prior retrograde tracing studies in which we mapped the location of IL-1beta-activated VLM and NTS cells that project to the mPVN. Both VLM and NTS lesions reduced the mPVN CRH and OT cell responses to IL-1beta. Unlike VLM lesions, NTS lesions also suppressed the recruitment of central amygdala neurons. These studies provide novel evidence that both the NTS and VLM catecholamine cells have important, but differential, contributions to the generation of IL-1beta-induced HPA axis responses.

Cocaine-specific neuroplasticity in the ventral striatum network is linked to delay discounting and drug relapse

AIMS: To contrast functional connectivity on ventral and dorsal striatum networks in cocaine dependence relative to pathological gambling, via a resting-state functional connectivity approach; and to determine the association between cocaine dependence-related neuroadaptations indexed by functional connectivity and impulsivity, compulsivity and drug relapse. DESIGN: Cross-sectional study of 20 individuals with cocaine dependence (CD), 19 individuals with pathological gambling (PG) and 21 healthy controls (HC), and a prospective cohort study of 20 CD followed-up for 12 weeks to measure drug relapse. SETTING AND PARTICIPANTS: CD and PG were recruited through consecutive admissions to a public clinic specialized in substance addiction treatment (Centro Provincial de Drogodependencias) and a public clinic specialized in gambling treatment (AGRAJER), respectively; HC were recruited through community advertisement in the same area in Granada (Spain). MEASUREMENTS: Seed-based functional connectivity in the ventral striatum (ventral caudate and ventral putamen) and dorsal striatum (dorsal caudate and dorsal putamen), the Kirby delay-discounting questionnaire, the reversal-learning task and a dichotomous measure of cocaine relapse indicated with self-report and urine tests. FINDINGS: CD relative to PG exhibit enhanced connectivity between the ventral caudate seed and subgenual anterior cingulate cortex, the ventral putamen seed and dorsomedial pre-frontal cortex and the dorsal putamen seed and insula (P≤0.001, kE=108). Connectivity between the ventral caudate seed and subgenual anterior cingulate cortex is associated with steeper delay discounting (P≤0.001, kE=108) and cocaine relapse (P≤0.005, kE=34). CONCLUSIONS: Cocaine dependence-related neuroadaptations in the ventral striatum of the brain network are associated with increased impulsivity and higher rate of cocaine relapse.

A biogeographically mixed, Middle Permian brachiopod fauna from the Baoshan Block, Western Yunnan, China

A small brachiopod fauna is described from the carbonate rocks of the basal Shazipo Formation of the Baoshan Block, western Yunnan, south-west China, including significant new ventral and dorsal internal morphological features of Cryptospirifer omeishanensis Huang. This fauna is regarded as Wordian (Middle Guadalupian, Middle Permian) because of the presence of Cryptospirifer omeishanensis Huang and associated fusulinids (Neoschwagerina craticulifera Zone). Palaeobiogeographically, the brachiopod fauna is of considerable interest because of its admixed nature characterized by typical warm-water Cathaysian elements intermingled with temperate Peri-Gondwanan taxa. This in turn is interpreted to indicate that the Baoshan Block may have been situated in an intermediate palaeogeographical position between Gondwanaland to the south and Cathaysia to the north during the Mid Permian and, as such, it probably furnished an important 'stepping stone' for the dispersal of Mid Permian eastern Tethyan marine invertebrate taxa (e.g. Cryptospirifer) to the western Tethys.

Linshuichonetes gen. nov., a new rugosochonetid (Brachiopoda) genus from the Liangshan Formation (Early Permian) in Sichuan, China, and its ecology

A new genus and species, Linshuichonetes elfinis, belonging to the Rugosochonetidae, is described from the Early Permian (Late Artinskian or early Kungurian) Liangshan Formation of the Yangtze block. The new genus is defined externally by the presence of fine, but delayed, capillation and a weak or absent median sulcus and fold and by the presence of a distinct posteromedian sinus on the ventral umbo; and internally by a lack of median, lateral and accessory septa in the dorsal interior; absence of vascular trunks in the ventral interior and the presence of distinct radiating rows of papillae in the interior of both valves, particularly an unusual clustered arrangement of papillae on the posteromedian portion of the dorsal interior. The local environment during the deposition of the Liangshan Formation appears to have been a restricted tidal flat or lagoon which experienced frequent sealevel fluctuations associated with the onset of the Yanghsingian transgression. The new species, L. elfinis, appears to have several morphological adaptations enabling successful exploitation of this environment. It was typically a very small and thin-valved species with a high surface area to volume ratio, an advantage in an oxygen restricted environment. The small size and numerous body spinules would have aided individuals to remain suspended at the top of the fine, soft substrate. It also dominated the brachiopod assemblage in the Liangshan Formation, comprising up to 94%of specimens within a bed. These factors indicate that the new species appears to be an opportunistic species.

Creatine supplementation and riluzole treatment provide similar beneficial effects in copper, zinc superoxide dismutase (G93A) transgenic mice

This study investigated the effects of riluzole (Ril), creatine (Cr) and a combination of these treatments on the onset and progression of clinical signs and neuropathology in an animal model of familial amyotrophic lateral sclerosis, the G93A transgenic mouse (n=13–17 per group). The onset of clinical signs was delayed (P<0.05) by about 12 days in all treatment groups compared with control; however, no differences occurred between treatments. All animals were killed at 199 days of age. At the end of the experimental period the severity of clinical signs was less (P<0.05) with all treatments compared with control. Again no differences between treatments were observed. The treatments had no effect on the number of neurons in ventral horns of the lumbar region of the spinal cord. Transgenic mice ingesting Cr displayed elevated (P<0.05) total Cr levels in cerebral hemispheres (5%) and spinal cord (8%), but not skeletal muscles. These data demonstrate that treatment with Ril and Cr were both effective in delaying disease onset and clinical disability. To the age of killing, no additional benefit was conferred by co-administration of Ril and Cr.

Nitric oxide control of large veins in the toad Bufo marinus

This study examined the nitric oxide (NO) control of the vascular smooth muscle of the ventral abdominal vein and vena cava of the toad, Bufo marinus, by using anatomical and physiological approaches. Nicotinamide adenine di-nucleotide phosphate-diaphorase histochemistry and immunohistochemistry using endothelial nitric oxide synthase (NOS) and neural NOS antibodies produced no evidence for endothelial NOS in the veins, but, neural NOS-immunoreactive perivascular nerves were present. Acetylcholine (10^–5 M) caused a vasodilation in both veins that was endothelium-independent, and which was blocked by the soluble guanylyl cyclase inhibitor, ODQ (10^–5 M). The NOS inhibitors, L-NNA (10^–4 M) and L-NAME (10^–4 M), did not significantly reduce the vasodilatory effect of acetylcholine in the veins; this suggested that the vasodilation was not due to NO. However, in the presence of phenoxybenzamine (10^–7–10^–8 M), L-NNA significantly reduced the vasodilatory effect of acetylcholine in the veins. This unusual response is due to phenoxybenzamine partially inactivating the muscarinic receptor pool in the veins. In addition, the neural NOS inhibitor, vinyl-L-NIO (10^–5 M), significantly reduced the acetylcholine-mediated vasodilation in the presence of phenoxybenzamine. The results show that in toad veins, nitrergic nerves rather than an endothelial NO system are involved in NO-mediated vasodilation.

Lipid characterisation and distribution in the fillet of the farmed Australian native fish, Murray cod (Maccullochella peelii peelii)

The objective of this study was to determine the distribution pattern of lipids and fatty acids in different tissues of farmed Murray cod (Maccullochella peelii peelii).

Differences in lipid content were found amongst different portions of the fillet, being lowest in the dorsal/cranial portion (P1) and highest in the more ventral/caudal portion (P8) (P < 0.05). The latter also recorded the highest amount of monounsaturated fatty acid (MUFA) and the lowest in polyunsaturated fatty acids (PUFA), arachidonic acid, 20:4n − 6 (ArA), docosahexaenoic acid, 22:6n − 3, (DHA) and the n3/n6 ratio. In general, lipid content in the different fillet portions was inversely correlated to PUFA and directly to MUFA. Contents of saturated fatty acids (SFA) and eicosapentaenoic acid, 20:5n − 3 (EPA) did not show any discernible trends in the different fillet portions, while significant differences in contents of DHA and ArA were observed. This study shows that lipid deposition in Murray cod varies markedly and that different fatty acids are deposited differently throughout the fillet.

Internal structure and paleoecology of the lower Permian Uzunbulak reef complex of the Tarim Basin, Northwest China

The internal construction and biotic communities of the Uzunbulak reef of the northwestern Tarim Basin are studied for the first time. The reef was built during the Sakmarian, while the reef substrate and capping beds are of latest Asselian and earliest Artinskian ages, respectively. The reef substrate beds are composed of skeletal and oncoid grainstone. Those fusulinid-dominated skeletal shoals and oncoid banks indicate a high-energy environment and produced local topographic highs on which the reef grew. Reef framework consists mainly of calcisponge bafflestone, calcisponge-Thartharella framestone, and Tubiphytes, Archaeolithoporella and Girvanella boundstones. Calcisponges were the primary frameconstructors that baffled high-energy currents. Archaeolithoporella, Tubiphytes, Girvanella and possibly microbes acted as the primary binders for the boundstone framework. Fusulinids and brachiopods were common reef dwellers. The interreef facies sediments are composed of skeletal-crinoid wackestone-packstone. Most of bioclasts have thick, micritized envelopes. The back-reef facies deposits consist of alternating skeletal packstone to wackestone and black shale. Sea-level fluctuations were probably accountable for the reef growth and demise.

Of the reefal dwellers, brachiopods are extraordinarily abundant in Uzunbulak. They are assignable to five distinctive associations, one each from the reef substrate, framework and inter-reef facies, respectively, and two from the reef capping facies. The brachiopods in the substrate beds were mostly attached to hard substrates by a pedicle, while a few species rested on soft substrates by support of halteroid spines. Cementation of the ventral valve on hard substrates characterizes attachment of the reef framework brachiopods. All inter-reef species were anchored into the substratum comprising hard material by a strong pedicle. Back-reef brachiopods dominantly rested on the soft substrates by support of halteroid spines. the framework brachiopods had the strongest wave-resistant capability;those from both substrate and inter-reef facies were moderately capable of withstanding agitation; and the backreef species preferred to live in calmwater, organic-rich muddy environments.

Lipid characterisation of different tissues and fillet portions of intensively farmed Murray Cod Maccullochella peelii peelii

Although many studies have focused on the lipid and fatty acids composition of farmed fish, no many have investigated their deposition pattern in different portions of the fillet. Previous studies, mainly on salmonids, have shown that lipids distribution varies greatly depending on the species, portion and type of muscle, but nevertheless, there is not accurate description of its deposition pattern in many fish, in particular in warm water, freshwater carnivorous species. Murray cod is the largest Australian native freshwater carnivorous fish and supports a small but well established and fast growing industry. The objective of this study was therefore to determine if there was any difference in lipid and fatty acid in different tissues such as muscle, liver and perivisceral fat and in different portions of the fillet of farmed Murray cod.

Three size fish (small, medium and large), all fed the same commercial diet, were selected from a commercial intensive farm. The left fillet of each fish was sectioned into nine portions, according to muscle lines and main anatomical features. The nine portions as well as whole right fillet, liver and perivisceral fat were analysed for proximate and fatty acid composition (Table 1).

Differences in lipid content were found amongst different portions of the fillet, with the dorsal/cranial portion (P1) recording the lowest and the more ventral/caudal portion (P8) recording the highest (P<0.05) value. The latter also recorded the highest amount of monounsaturated fatty acid (MUFA) and the lowest of polyunsaturated fatty acids (PUFA), arachidonic acid, 20:4n-6 (ArA), docosahexaenoic acid, 22:6n-3, (DHA) and n3/n6 ratio. In general, lipid content in the different fillet portions was inversely correlated to PUFA and directly to MUFA. Saturated fatty acid (SFA) and eicosapentaenoic acid, 20:5n-3 (EPA) did not show any discernible trend and were similar throughout, while significant differences of DHA and ArA content were observed. This study shows that lipid deposition in Murray cod varies remarkably and that different fatty acids are deposited at different rates. The results of this study show how different adjacent portions can be and therefore attention need to be paid when conducting chemical, nutritional and sensorial analyses on Murray cod.

Influence of temperature on evaporative water loss and cutaneous resistance to water vapour diffusion in the orange-thighed frog (Litoria xanthomera)

We evaluated the effect of ambient temperatures between 25 and 43°C on the rate of evaporative water loss (EWL) in eight adult Litoria xanthomera (average body mass = 7.3 ± 0.6 g). Frogs were placed in a cylindrical chamber that permitted them to fully conceal their ventral surfaces using a water-conserving posture. Their EWL was 7.1 ± 0.7 mg g^–1 h^–1 at 25°C and reached 28.0 ± 2.5 mg g^–1 h^–1 at 43°C. Agar replicas of the frogs were used to evaluate boundary-layer resistances associated with the EWL measurements and, thus, to permit evaluation of cutaneous resistance to vapour diffusion (r_c) in live frogs. The r_c of L. xanthomera was stable over the temperature range of 25–35°C, averaging about 28 s cm^–1, and then declined stepwise with ambient temperatures above 37°C. The highest r_c recorded for each individual over the range of temperatures studied averaged 32.0 ± 1.2 s cm^–1. The thermolabile nature of r_c demonstrates a well developed thermoregulatory control of EWL in this species, a trait very similar in pattern and extent to that previously measured in the closely related Litoria chloris.

Comparative distribution of a putative egg-laying hormone in neural and reproductive tissues of four Decapoda crustaceans

Evidence for the presence of a putative egg-laying (ELH) hormone has been previously described in the black tiger shrimp, Penaeus monodon, so a further investigation was carried out to detect its presence in a range of Decapoda crustaceans prior to a full molecular analysis. The crustaceans were represented by the Australian fresh water yabbie, Cherax destructor, the Australian southern rock lobster, Jasus edwardsii, the snow crab, Chionoecetes opilio, and the blue swimmer crab, Portunus pelagicus. Female cerebral ganglia, ventral nerve cords and gonads were investigated in a comparative study of the distribution of the immunoreactive hormone using immunoenzyme and immunofluorescence techniques. Immunoreactivity was detected in all tissues of interest, and the distribution patterns showed similarity within the four species, as well as that of P. monodon reported in the earlier study. There were minor variations. These data indicate that a putative ELH-like neuropeptide is widespread in crustaceans, and supports its previous identification in a range of molluscs and other invertebrates. Elucidation of the molecular structure of the peptide hormone and its encoding gene, as well as its involvement in spawning behaviour of crustaceans, is now fully under investigation.

Studies on dietary fibre : analysis, epidemiological and physiological aspects

This thesis involves an investigation in three areas; first, a study of an enzymatic-gravimetric method for the analysis of dietary fibre; second, a survey of dietary fibre intake in an area of a developing country, and finally, some observations on the functional aspects of gel-forming dietary fibre in the rat. A simple and rapid enzymatic-gravimetric assay for both soluble and insoluble dietary fibre has been critically investigated. Reference samples were also analysed by a more comprehensive, enzymatic gas chromatographic method to allow testing of the relative accuracy of the enzymatic-gravimetric method. The enzymatic-gravimetric method was found to be highly reproducible but gave a slightly higher value for total dietary fibre than the more comprehensive method. This discrepancy is probably due to the presence of small quantities of resistant starch and protein residue which are recovered in the enzymatic-gravimetric method. In the enzymatic-gas chromatographic method, protein residue is not measured, and resistant starch is estimated, but not counted as dietary fibre. The enzymatic-gravimetric method was applied to the analysis of foods commonly consumed in the Padang region of West Sumatra in Indonesia, in order to estimate dietary fibre intake in the region. Daily intakes of usual foods were estimated by use of a 24-hour recall procedure aided by food photographs to assist in the estimation of portion size. Samples of approximately 60 of the most commonly consumed foods were collected and analysed for dietary fibre. These appear to be the first data which report values for dietary fibre in Indonesion foods and they represent a significant improvement upon the existing data on crude fibre content. Knowledge of the amounts of foods usually consumed and their dietary fibre content allowed an estimation of usual intakes of dietary fibre. Fibre intake was found to be lower than in the developing countries of Africa and was comparable to intakes measured in the U.K. This is the first study to show that in this part of South East Asia, a developing country area using polished rice as a staple food, dietary fibre intakes are as low as in Western countries. Low intakes of fibre are believed to be related to the prevalence of a range of diseases and, in this study, preliminary data on the rates of non-infective, chronic diseases were collected from the two main hospitals in West Sumatra. Chronic, non-infectious diseases such as inguinal hernia, appendicitis, haemorrhoids, diabetes mellitus, hypertension and malignant neoplasms of the rectum are relatively frequent in West Sumatra. While no firm conclusions can be drawn from these data, they do show the possibility of a relationship between low intakes of dietary fibre and the prevalence of these diseases, and suggest that further investigation is necessary. Some observations were made of the effect of gel-forming dietary fibre on stomach emptying and intestinal transit rate in the rat. Xanthan gum was added to iso-osmotic solutions to produce increased viscosity and phenol sulphonphthalein (phenol red) was used as a non-absorbable marker. Gavage feeding of solutions with a range of viscosities was used to study the effect of viscosity on the rate of stomach emptying and intestinal transit. Increased viscosity was observed to slow gastro-intestinal transit and this provides one mechanism by which dietary fibre of the gel-forming type ray improve glucose tolerance.

Ontogeny of putative GABAergic neurons and their receptors in the nervous system of the crayfish Cherax destructor

Inhibitory neurons exert control the expression of many aspects of behaviour by regulating the effectiveness of excitatory neural function. By comparison with excitatory neural systems, relatively little is known about the development of inhibitory neurons and the influence which these neurons exert on the development of other neural systems. Two issues which relate to the development of inhibitory neurons are of particular interest. First, a paradox arises when inhibitory neurons are considered in terms of modern models of synaptic development which involve activity-dependent mechanisms of synaptic plasticity. Second, there is some evidence that inhibitory neurotransmitters may act in a special trophic manner during the early development of nervous systems. Investigations of these issues would be greatly facilitated in a neural system in which it was possible to experimentally control aspects of the development of individual pre- and postsynaptic cells. The aim of the results presented in this thesis was to characterise the normal development of one such system: the GABAergic inhibitory system of the Australian freshwater crayfish, Cherax destructor. The ontogeny of the inhibitory neurotransmitter GABA across the embryonic period of 30% to 100% development was investigated using immunohistochemical techniques. GABA-like immunoreactive cells and fibres were first detected in the embryonic brain region. The expression of GABA-like immunoreactivity progressed along a rostro-caudal gradient, with GABA-like immunoreactive cells being detected in the most anterior thoracic ganglia at 45% development and in all ganglia by 65% development. GABA-like immunoreactive fibres were evident in peripheral nerves as early as 55% development and ramified extensively throughout the neuropil of the nervous system by 65% development. By contrast, immunoreactivity to the primary excitatory neurotransmitter, glutamate, was not detected until 60-65% development. Glutamate-like immunoreactivity at 60-65% development was evident only in the form of punctate staining in the midline of the ventral nerve cord. Cell body staining was observed only at 90% development and was restricted to only a few cells on the periphery of the ventral nerve cord. Radio-labelled ligand binding methods and autoradiography were used to study the expression of putative GABA receptors in the Cherax embryos from 30% to 100% development. Specific binding was evident in the earliest embryos studies at 30% development. There was an initial increase in binding from 30% to 40% development, followed by a dramatic drop to almost zero binding at 50-55% development. This was followed by a gradual increase in binding levels with age, reaching a plateau at 85% development. Preliminary pharmacological evaluation of binding indicated that at least three GABA receptor types were expressed during embryonic development. Methods for culturing, dissociated neural tissues explanted form Cherax embryos at 85% development were established. The success of cultures was demonstrated by neurite extension, and neuronal networks in which neurons appeared to form connections with other neurons and with explanted muscle cells after two days in culture. Immunohistochemical studies demonstrated that some explanted neurons expressed GABA-like immunoreactivity within two days of explanting. These studies have provided a comprehensive description of the development of GABAergic neurons and their receptors in Cherax destructor embryos. The very early expression of GABA-like immunoreactivity, coupled with the early onset of specific GABA binding, strongly indicates that the GABAergic neurons are functional and able to exert an effect on other cells during much of the period of nervous system development in crayfish embryos. These results support the hypothesis that inhibitory neurons may play an important role as regulators of the overall process of assembly and maturation of the nervous system and provide a substantial basis for future experimental studies in which the specific action of inhibitory neurons on the development of discrete components of the crayfish nervous system may be investigated.

The existence of gonadotropin-releasing hormone-like peptides in the neural ganglia and ovary of the abalone, Haliotis asinina L.

Gonadotropin-releasing hormone (GnRH) is a neuropeptide that is conserved in both vertebrate and invertebrate species. In this study, we have demonstrated the presence and distribution of two isoforms of GnRH-like peptides in neural ganglia and ovary of reproductively mature female abalone, Haliotis asinina, using immunohistochemistry. We found significant immunoreactivities (ir) of anti-lamprey(I) GnRH-III and anti-tunicate(t) GnRH, but with variation of labeling intensity by each anti-GnRH type. IGnRH-III-ir was detected in numerous type1 neurosecretory cells (NS1) throughout the cerebral and pleuropedal ganglia, whereas tGnRH-I-ir was detected in only a few NS1 cells in the dorsal region of cerebral and pleuropedal ganglia. In addition, a small number of type2 neurosecretory cells (NS2) in cerebral ganglion showed lGnRH-III-ir. Long nerve fibers in the neuropil of ventral regions of the cerebral and pleuropedal ganglia showed strong tGnRH-I-ir. In the ovary, lGnRH-III-ir was found primarily in oogonia and stage I oocytes, whereas tGnRH-ir was observed in stage I oocytes and some stage II oocytes. These results indicate that GnRH produced in neural ganglia may act in neural signaling. Alternatively, GnRH may also be synthesized locally in the ovary where it could induce oocytes development.