bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical Constituents of Dichloromethane Extract of Cultivated Satureja khuzistanica
Authors: Moghaddam Firouz Matloubi , Farimani Mahdi Moridi , Salahvarzi Sabah , Amin Gholamreza
Published: September 2006

Four compounds β‐sitosterol, β‐sitosterol‐3‐O‐β‐d‐glucopyranoside, ursolic acid and 4′,5,6‐trihydroxy‐3′, 7‐dimethoxyflavone were characterized from the dichloromethane extract of the aerial parts of Satureja khuzistanica (Lamiaceae), a native medicinal plant growing in Iran, on the basis of spectral analysis and comparing with the data in literature. The natural occurrence of these compounds can be conclusive for the chemotaxonomic characterization of the genus Satureja.
Fatigable Swallowing in Myasthenia Gravis-Proposal of a Standardized Test and Report of a Case
Authors: Dziewas Rainer , Warnecke Tobias , Ritter Martin , Dittrich Ralf , Schilling Matthias , Schabitz Wolf Rudiger , Ringelstein Erich Bernd , Nabavi Darius G
Published: September 2006

Myasthenia gravis (MG) is clinically characterized by fatigable muscle weakness. Because dysphagia is a frequent and important symptom in patients with MG, an adequate diagnostic approach is mandatory. In this article, we describe a standardized endoscopic examination called “fatigable swallowing test” that allows for a precise grading of dysphagia in patients with MG. By reporting on a patient with mainly bulbar MG, the use of this new instrument is illustrated.
Lambert-Eaton Syndrome With Thymic Hyperplasia
Authors: Abdel-Hamid Hoda , Lacomis David
Published: September 2006

In a patient with Lambert-Eaton syndrome, an intrathoracic mass is usually malignant. We report the clinical and diagnostic findings of a patient with Lambert-Eaton syndrome and autoimmune thyroiditis who was found to have a mediastinal mass caused by benign thymic lymphoid hyperplasia. This association is rare, and we discuss the potential pathophysiologic implications.
Altered host behaviour and brain serotonergic activity caused by acanthocephalans: evidence for specificity
Authors: Tain Luke , Perrot-Minnot Marie-Jeanne , Cézilly Frank
Published: September 2006

Manipulative parasites can alter the phenotype of intermediate hosts in various ways. However, it is unclear whether such changes are just by-products of infection or adaptive and enhance transmission to the final host. Here, we show that the alteration of serotonergic activity is functionally linked to the alteration of specific behaviour in the amphipodGammarus pulexinfected with acanthocephalan parasites.Pomphorhynchus laevisand, to a lesser extent,Pomphorhynchus tereticollisaltered phototactism, but not geotactism, inG. pulex, whereas the reverse was true forPolymorphus minutus. Serotonin (5-hydroxytryptamine, 5-HT) injected to uninfectedG. pulexmimicked the altered phototactism, but had no effect on geotactism. PhotophilicG. pulexinfected withP. laevisorP. tereticollisshowed a 40% increase in brain 5-HT immunoreactivity compared to photophobic, uninfected individuals. In contrast, brain 5-HT immunoreactivity did not differ betweenP. minutus-infected and uninfectedG. pulex. Finally, brain 5-HT immunoreactivity differed significantly amongP. tereticollis-infected individuals in accordance with their degree of manipulation. Our results demonstrate that altered 5-HT activity is not the mere consequence of infection by acanthocephalans but is specifically linked to the disruption of host photophobic behaviour, whereas the alteration of other behaviours such as geotactism may rely on distinct physiological routes.
Genetic models of homosexuality: generating testable predictions
Authors: Gavrilets Sergey , Rice William R
Published: September 2006

Homosexuality is a common occurrence in humans and other species, yet its genetic and evolutionary basis is poorly understood. Here, we formulate and study a series of simple mathematical models for the purpose of predicting empirical patterns that can be used to determine the form of selection that leads to polymorphism of genes influencing homosexuality. Specifically, we develop theory to make contrasting predictions about the genetic characteristics of genes influencing homosexuality including: (i) chromosomal location, (ii) dominance among segregating alleles and (iii) effect sizes that distinguish between the two major models for their polymorphism: the overdominance and sexual antagonism models. We conclude that the measurement of the genetic characteristics of quantitative trait loci (QTLs) found in genomic screens for genes influencing homosexuality can be highly informative in resolving the form of natural selection maintaining their polymorphism.
Spontaneous gene flow from rapeseed (Brassica napus) to wildBrassica oleracea
Authors: Ford Caroline S , Allainguillaume Joël , Grilli-Chantler Phil , Cuccato Giulia , Allender Charlotte J , Wilkinson Mike J
Published: September 2006

Research on the environmental risks of gene flow from genetically modified (GM) crops to wild relatives has traditionally emphasized recipients yielding most hybrids. For GM rapeseed (Brassica napus), interest has centred on the ‘frequently hybridizing’Brassica rapaover relatives such asBrassica oleracea, where spontaneous hybrids are unreported in the wild. In two sites, where rapeseed and wildB. oleraceagrow together, we used flow cytometry and crop-specific microsatellite markers to identify one triploid F1hybrid, together with nine diploid and two near triploid introgressants. Given the newly discovered capacity for spontaneous introgression intoB. oleracea, we then surveyed associated flora and fauna to evaluate the capacity of both recipients to harm cohabitant species with acknowledged conservational importance. OnlyB. oleraceaoccupies rich communities containing species afforded legislative protection; these include one rare micromoth species that feeds onB. oleraceaand warrants further assessment. We conclude that increased attention should now focus onB. oleraceaand similar species that yield few crop-hybrids, but possess scope to affect rare or endangered associates.
Negotiations within the family over the supply of parental care
Authors: Hinde Camilla A , Kilner Rebecca M
Published: September 2006

Adults provisioning dependent young are in conflict with their partners, who would prefer a greater level of effort, and with their offspring, who would prefer a greater supply of food. To what extent, then should adults negotiate their provisioning behaviour with other family members? We used experimental manipulations of brood size, and targeted playback of begging calls to determine the extent to which adult great titsParus majoradjust their provisioning rates in response to the behaviour of their partner and their brood. We found that males and females behaved similarly, both responding more to each other's behaviour than to chick calling. We also found that the degree to which adults negotiated their provisioning rates with each other varied between years. A review of the literature suggests that the extent of negotiation over provisioning is likely to vary not only between species of diverse taxa, but also between and within (this study) populations of the same species. We suggest that provisioning behaviour lies on a ‘negotiation continuum’, which describes the extent to which parents respond to the actions of other family members. We argue that an individual's location on the ‘negotiation continuum’ is determined partly by the extent to which it can physically respond to the behaviour shown by other members of the family and partly by the quality of information on offer.
Queen promiscuity lowers disease within honeybee colonies
Authors: Seeley Thomas D , Tarpy David R
Published: September 2006

Most species of social insects have singly mated queens, but in some species each queen mates with numerous males to create a colony with a genetically diverse worker force. The adaptive significance of polyandry by social insect queens remains an evolutionary puzzle. Using the honeybee (Apis mellifera), we tested the hypothesis that polyandry improves a colony's resistance to disease. We established colonies headed by queens that had been artificially inseminated by either one or 10 drones. Later, we inoculated these colonies with spores ofPaenibacillus larvae, the bacterium that causes a highly virulent disease of honeybee larvae (American foulbrood). We found that, on average, colonies headed by multiple-drone inseminated queens had markedly lower disease intensity and higher colony strength at the end of the summer relative to colonies headed by single-drone inseminated queens. These findings support the hypothesis that polyandry by social insect queens is an adaptation to counter disease within their colonies.
Opsin gene duplication and diversification in the guppy, a model for sexual selection
Authors: Hoffmann Margarete , Tripathi Namita , Henz Stefan R. , Lindholm Anna K. , Weigel Detlef , Breden Felix , Dreyer Christine
Published: September 2006

Identification of genes that control variation in adaptive characters is a prerequisite for understanding the processes that drive sexual and natural selection. Male coloration and female colour perception play important roles in mate choice of the guppy, a model organism for studies of natural and sexual selection. We examined a potential source for the known variation in colour perception, by analysing genomic and complementary DNA sequences of genes that code for visual pigment proteins. We find high sequence variability, both within and between populations, and expanded copy number for long-wave sensitive (LWS) opsin genes. Alleles with non-synonymous changes that suggest dissimilar spectral tuning properties occur in the same population and even in the same individual, and the high frequency of non-synonymous substitutions argues for diversifying selection acting on these proteins. Therefore, variability in tuning amino acids is partitioned within individuals and populations of the guppy, in contrast to variability for LWS at higher taxonomic levels in cichlids, a second model system for differentiation owing to sexual selection. Since opsin variability parallels the extreme male colour polymorphism within guppy populations, we suggest that mate choice has been a major factor driving the coevolution of opsins and male ornaments in this species.
: the driver of giant planet atmospheres
Authors: Miller Steve , Stallard Tom , Smith Chris , Millward George , Melin Henrik , Lystrup Makenzie , Aylward Alan
Published: September 2006

We present a review of recent developments in the use of

molecular ion as a probe of physics and chemistry of the upper atmospheres of giant planets. This ion is shown to be a good tracer of energy inputs into Jupiter (J), Saturn (S) and Uranus (U). It also acts as a ‘thermostat’, offsetting increases in the energy inputs owing to particle precipitation via cooling to space (J and U). Computer models have established that

is also the main contributor to ionospheric conductivity. The coupling of electric and magnetic fields in the auroral polar regions leads to ion winds, which, in turn, drive neutral circulation systems (J and S). These latter two effects, dependent on

, also result in very large heating terms, approximately 5×10
12
 W for Saturn and greater than 10
14
 W for Jupiter, planet-wide; these terms compare with approximately 2.5×10
11
 W of solar extreme UV absorbed at Saturn and 10
12
 W at Jupiter. Thus,

is shown to play a major role in explaining why the temperatures of the giant planets are much greater (by hundreds of kelvin) at the top of the atmosphere than solar inputs alone can account for.
Pseudolabrys taiwanensis gen. nov., sp. nov., an alphaproteobacterium isolated from soil
Authors: Kämpfer Peter , Young Chiu-Chung , Arun A. B. , Shen Fo-Ting , Jäckel Udo , Rosselló-Mora Ramon , Lai Wei-An , Rekha P. D.
Published: September 2006

A Gram-negative, short rod-shaped micro-organism (CC-BB4T) was isolated on nutrient agar from soil from Sinshe in Taichung County, Taiwan. Analysis of the 16S rRNA gene sequence demonstrated that this isolate was novel, as it showed <92 % similarity to the sequences of species of the genera Labrys, Beijerinckia and Methylocystis. The micro-organism did not utilize methylamine or methanol as a substrate, but was able to use several organic acids. The fatty acid profile was different from those reported for the genera Labrys, Beijerinckia, Methylocystis, Angulomicrobium, Methylorhabdus and Methyloarcula. On the basis of the 16S rRNA gene sequence analysis, in combination with chemotaxonomic and physiological data, strain CC-BB4T represents a novel genus, for which the name Pseudolabrys gen. nov. is proposed. The type species is Pseudolabrys taiwanensis sp. nov., and the type strain of P. taiwanensis is CC-BB4T (=CCUG 51779T=CIP 108932T).
Oenococcus kitaharae sp. nov., a non-acidophilic and non-malolactic-fermenting oenococcus isolated from a composting distilled shochu residue
Authors: Endo Akihito , Okada Sanae
Published: September 2006

Six strains of lactic acid bacteria were isolated in Japan from a composting distilled shochu residue. The six isolates grew poorly on MRS agar and slowly in MRS broth. The 16S rRNA gene sequences did not show high levels of similarity to those of the recognized species of lactic acid bacteria, and formed a subcluster within the cluster comprising obligately heterofermentative lactic acid bacteria closely related to Oenococcus oeni. The levels of DNA–DNA relatedness revealed that the isolates belonged to the same taxon and were genetically separate from O. oeni. Furthermore, various phenotypic characteristics such as the optimum pH for growth, malolactic fermentation and resistance to 10 % ethanol revealed that the isolates are distinguishable from O. oeni. On the basis of their phylogenetic and phenotypic characteristics, the isolates represent a novel species, for which the name Oenococcus kitaharae sp. nov. is proposed. The type strain is NRIC 0645T (=JCM 13282T=DSM 17330T).
Massilia aurea sp. nov., isolated from drinking water
Authors: Gallego Virginia , Sánchez-Porro Cristina , García Maria Teresa , Ventosa Antonio
Published: September 2006

A Gram-negative, motile, rod-shaped organism, strain AP13T, able to produce yellow-pigmented colonies, was isolated from the drinking water distribution system of Seville (Spain) and was characterized by using a polyphasic taxonomic approach. In 16S rRNA gene sequence comparisons, strain AP13T exhibited 96.9–95.6 % similarity with respect to the five recognized species of the genus Massilia. The DNA G+C content of strain AP13T was 66.0 mol%, a value that supports the affiliation of strain AP13T to the genus Massilia. DNA–DNA hybridization data and phenotypic properties confirmed that strain AP13T represents a novel species of the genus Massilia, for which the name Massilia aurea sp. nov. is proposed. The type strain is AP13T (=CECT 7142T=CCM 7363T=DSM 18055T=JCM 13879T).
Description of Wautersiella falsenii gen. nov., sp. nov., to accommodate clinical isolates phenotypically resembling members of the genera Chryseobacterium and Empedobacter
Authors: Kämpfer Peter , Avesani Véronique , Janssens Michèle , Charlier Jacqueline , De Baere Thierry , Vaneechoutte Mario
Published: September 2006

A total of 26 isolates of non-fermenting, Gram-negative rods, obtained between 1980 and 2004 by various clinical laboratories in Belgium, with phenotypic characteristics resembling those of members of the genera Chryseobacterium and Empedobacter (indole-positive) and a biochemical profile resembling that of CDC group II-h, but urease-positive, were collected at the Université Catholique de Louvain Microbiology Laboratory, Belgium. The 16S rRNA gene sequences were determined for most of the isolates and showed 94–95 % similarity with the type strain of Empedobacter brevis as the closest relative, indicating that these isolates might belong to a separate genus. Furthermore, the 16S rRNA gene sequences of the isolates were similar, but two clusters (genomovars) could be distinguished. The sequence similarities were 99.5–100 % for the 14 isolates of genomovar 1 and 99.4–100 % for the 12 isolates of genomovar 2. The similarity between the two clusters was 98.3–99.5 %. The presence of two clearly different groups was corroborated by using tRNA intergenic length polymorphism analysis, which also enabled differentiation of the novel species from all other species studied thus far using this technique. DNA–DNA hybridization results excluded a close relatedness to Empedobacter brevis. The DNA G+C contents of the reference strains of genomovars 1 and 2 were 33.8±0.4 and 34.4±0.2 mol%, respectively. The name Wautersiella falsenii gen. nov., sp. nov., is proposed for this group, comprising two closely related genomovars. The type strain of the species and reference strain for genomovar 1 is NF 993T (=CCUG 51536T=CIP 108861T), which was isolated from a surgical wound. The reference strain for genomovar 2 is NF 770 (=CCUG 51537=CIP 108860), which was isolated from blood.
Metschnikowia orientalis sp. nov., an Australasian yeast from nitidulid beetles
Authors: Lachance Marc-André , Bowles Jane M. , Wiens Frank , Dobson Jessica , Ewing Curtis P.
Published: September 2006

A novel species, Metschnikowia orientalis sp. nov., is described for haploid, heterothallic yeasts isolated from nitidulid beetles sampled in flowers in Rarotonga in the Cook Islands, and the Cameron Highlands of Malaysia. As evidenced by analysis of D1/D2 large subunit rDNA sequences, the species is related to Candida hawaiiana, to which it is similar in growth responses. Cylindrical, conjugated asci and acicular ascospores of moderate size are formed. Rudimentary mating reactions were observed with Metschnikowia aberdeeniae and Metschnikowia continentalis, but not with C. hawaiiana. The type strain of M. orientalis is UWOPS 99-745.6T (h+) (=CBS 10331T=NRRL Y-27991T) and the designated allotype is UWOPS 05-269.1 (h−) (=CBS 10330=NRRL Y-27992).
PCR fingerprinting of Trichophyton mentagrophytes var. interdigitale using polymorphic subrepeat loci in the rDNA nontranscribed spacer
Authors: Jackson Colin J. , Mochizuki Takashi , Barton Richard C.
Published: September 2006

The sequence of the nontranscribed spacer (NTS) region of the rDNA of Trichophyton mentagrophytes var. interdigitale strain 2111 was determined, and three individual subrepeat loci identified. The first repeat region contained eight tandem copies of a degenerate 33–43 bp sequence, whilst the second had two complete and two partial 300 bp repeats. The third locus contained six tandemly repetitive elements of between 67 and 89 bp, which showed sequence identity to the TrS2 repeats of Trichophyton rubrum. PCR amplification of the individual repetitive regions from 42 random isolates of T. mentagrophytes var. interdigitale identified fragment length polymorphisms at each locus. Sequence analysis of the PCR products revealed that the size variations resulted from differences in the copy number of each of the three sets of subrepeat elements, TmiS0, TmiS1 and TmiS2. In addition, some indels were present in the flanking regions of the TmiS1 repeats. Combining PCR fingerprints from each of the three polymorphic loci produced a total of 19 individual strain profiles. The method was rapid, reproducible and discriminatory, and the fragment patterns simple to interpret. PCR fingerprint analysis of variable tandem repeat loci in the T. mentagrophytes var. interdigitale NTS represents a valuable molecular typing method for future epidemiological investigations in this species.
Glomerular expression and elevated serum Bcl-2 and Fas proteins in lupus nephritis: preliminary findings
Authors: Fathi N A , Hussein M R , Hassan H I , Mosad E , Galal H , Afifi N A
Published: September 2006

Programmed cell death (apoptosis) is involved in glomerular injuries leading to glomerulonephritis. Bcl-2 and Fas are proteins that promote cell survival and death, respectively. This study tests the hypothesis that lupus nephritis is associated with alterations of Bcl-2 and Fas protein expression. Thirty-six patients with lupus nephritis and 10 controls (normal individuals) were included in this study. Bcl-2 and Fas positive cells were examined in kidney biopsies by immunohistochemistry. Bcl-2 and Fas serum levels were evaluated by enzyme-linked immunosorbent assay (ELISA). In the glomeruli of normal kidneys, Bcl-2 and Fas proteins were completely absent. In lupus nephritis patients, glomerular expression of Bcl-2 and Fas was seen in mesangial cells (1·3 ± 0·1 and 2·0 ± 0·1 for Bcl-2 and Fas, respectively). Similarly, a statistically significantly higher Bcl-2 (217·1 ± 85·9) and Fas (767·9 ± 271) serum levels were found in lupus patients compared to controls (148·6 ± 87, 550·3 ± 91 for Bcl-2 and Fas, P < 0·05). A direct correlation between serum Bcl-2 and Fas and chronicity index was also found. Compared to normal controls, lupus nephritis is associated with glomerular expression and elevated serum levels of Bcl-2 and Fas proteins. These findings suggest possible roles for Bcl-2 and Fas in glomerular injury during evolution of lupus nephritis. The diagnostic, prognostic and therapeutic ramifications of our findings are open to further investigation.
Corticotrophin‐Releasing Hormone Stimulates Neurohypophyslal Hormone Release through an Interaction with the Intermediate Lobe of the Pituitary
Authors: Bondy C. A. , Gainer H.
Published: September 2006

Corticotrophin‐releasing hormone is found co‐localized with oxytocin in the magnocellular‐neurohypophysical system but its function in this context is unknown. We tested its effects on neurohypophysical hormone secretion in vitro, in the presence and absence of the intermediate lobe of the pituitary. Corticotrophin‐releasing hormone caused significant, calcium‐dependent secretion of oxytocin and vasopressin from neural lobes in contact with intermediate lobes, i.e. neurointermediate lobes. This effect was inhibited by the dopamine agonist, bromocriptine. Corticotrophin‐releasing hormone had no effect on isolated neural lobes in the absence of the intermediate lobe, but α‐ and γ‐melanocyte‐stimulating hormone produced an increase in secretion that was comparable in pattern and magnitude to the effect of corticotrophin‐releasing hormone on neurointermediate lobes. These findings suggest that corticotrophin‐releasing hormone released with oxytocin may act in a paracrine fashion to stimulate release of intermediate peptides which, in turn, can directly evoke release of oxytocin and vasopressin from neural lobe terminals.
The Perfusion of the Endogenous Neuropeptide, Phe‐Met‐Arg‐Phe‐NH2 (FMRFamide) through the Gill of Aplysia Potentiates the Gill Withdrawal Reflex Evoked by Siphon Stimulation and Prevents its Habituation
Authors: Higgins Andrew , Cawthorpe David , Lukowiak Ken
Published: September 2006

Perfusion of Phe‐Met‐Arg‐Phe‐NH2 (FMRFamide), an endogenous neuropeptide, through the gill of Aplysia significantly potentiates the amplitude of the gill withdrawal reflex evoked by tactile stimulation of the siphon with or without the central nervous system present. The potentiating effect of FMRFamide is reversible with washout. FMRFamide perfusion of the gill also prevented the gill withdrawal reflex from undergoing habituation when the tactile stimulus was presented repeatedly. Rather than habituate, the gill withdrawal reflex increased in amplitude. FMRFamide continued to prevent habituation in the absence of the parietal‐visceral ganglion. We hypothesize that FMRFamide plays a role in the mediation of behavioural state primarily by affecting activity in the peripheral nervous system in the gill.
Immunocytochemical Localization and Biochemical Characterization of α‐Melanocyte‐Stimulating Hormon in the Brain of the Rainbow Trout, Salmo gairdneri
Authors: Vallarino M. , Delbende C. , Ottonello I. , Tranchand‐Bunel D. , Jegou S. , Vaudry H.
Published: September 2006

The distribution of α‐melanocyte‐stimulating hormone (α‐MSH)‐like immunoreactivity in the central nervous system of the rainbow trout Salmo gairdneri was investigated by indirect immunofluorescence and peroxidase‐antiperoxidase techniques, using a highly specific antiserum generated in rabbits against synthetic α‐MSH. Immunoreactive perikarya were exclusively observed in the basal hypothalamus within the pars anterioris of the nucleus lateralis tuberis. In this region, a moderate number of small stained cell bodies were observed surrounding the dorsal wall of the anterior infundibular recess. These immunoreactive cells were organized in rostro‐caudal rows extending over the whole portion of the nucleus. Positive fibres originating from these perikarya were visualized in the dorsal posterior lobe and the ventral hypothalamus. A dense tract of immunoreactive fibres projected ventrally through the pituitary stalk and terminated in the neurohypophysis. The concentrations of α‐MSH in different regions of the brain were measured by means of a sensitive and specific radioimmunoassay. The dilution curves obtained with synthetic α‐MSH and serial dilutions of diencephalon, mesencephalon, medulla oblongata, telencephalon or pituitary extracts were strictly parallel. The highest concentration of α‐MSH in brain was found in the diencephalon (1.31 ± 0.07 ng/mg protein). In contrast α‐MSH was not detectable in cerebellar extracts. Reverse‐phase high‐performance liquid chromatography and radioimmunoassay were used to characterize α‐MSH‐like peptides in the trout brain and pituitary. Two major forms of immunoreactive α‐MSH were resolved by high performance liquid chromatography in hypothalamic extracts; these peptides exhibited the same retention times as des‐Na‐acetyl α‐MSH and its sulfoxide derivative, respectively. Additional peaks of α‐MSH immunoreactive material were detected in pituitary extract. These latter peptides coeluted with authentic α‐MSH, diacetyl α‐MSH and their sulfoxide forms. These results provide the first evidence for the presence of α‐MSH in the brain of a teleostean fish. Our data indicate that, in the brain, the immunoreactivity corresponds to the non‐acetylated form of α‐MSH, while three different types of α‐MSH‐like molecules (namely deacetylated, monoacetylated, and diacetylated forms) coexist in the pituitary. It thus appears that, in salmonoid fish, mono‐ or diacetylation of the N‐terminal serine residue of aL‐MSH only occurs at the pituitary level.
Modulation of Neuropeptide‐lnduced Membrane Currents by Protein Kinase C in Xenopus Oocytes Injected with GH3 Pituitary Cell Poly(A)+ RNA
Authors: Mahlmann Stefan , Schwarz Jürgen R. , Meyerhof Wolfgang
Published: September 2006

Protein kinase C was activated in Xenopus laevis oocytes by phorbol ester treatment and its effects on the inositol trisphosphate/Ca2+ transmembrane signalling pathway analysed. Induction of the pathway was achieved by ligand stimulation of TRH receptors translated from GH3 pituitary cell mRNA. In voltage‐clamped oocytes bath application of peptide, injection of guanosine 5′‐(3‐O‐thio) triphosphate (GTPγS), inositol trisphosphate or Ca2+ all elicited inward membrane currents. Treatment of oocytes with tumour‐promoting phorbol esters for 35 min almost completely abolished the ligand and GTPγS‐induced responses. In contrast, phorbol ester treatment enhanced inositol trisphosphate‐generated membrane currents. Ca2+‐mediated responses remained unaffected by tumour promoters. The data indicate a dual role for protein kinase C in the modulation of transmembrane signalling: a feedback mechanism prevents phosphoinositide turnover whereas a feedforward reaction triggers the effect of intracellular inositol trisphosphate on the Ca2+ release.
Simultaneous Visualization of Vasopressin and Oxytocin mRNA‐ Containing Neurons in the Hypothalamus Using Non‐Radioactive in situ Hybridization Histochemistry
Authors: Ichimiya Yosuke , Emson Piers C. , Christodoulou Chris , Gait Michael J. , Ruth Jerry L.
Published: September 2006

In situ hybridization histochemistry (ISHH) using synthetic oligodeoxynucleotide probes has been used to demonstrate the sites of expression of mRNA for vasopressin (AVP) and oxytocin (OXT) in the rat brain. ISHH was performed with two types of non‐radioactive probes, labelled with either alkaline phosphatase or 5′‐biotin. Simultaneous detection of the mRNAs for both AVP and OXT was achieved using an alkaline phosphatase substrate for the AVP probe and an anti‐biotin monoclonal (mouse) antibody for the OXT probe. These probes revealed two non‐overlapping populations of AVP and OXT neurons on the same section.
Corticotrophin‐Releasing Factor Antagonist [alpha helical CRF(9–41)] Blocks Central Noradrenaline‐lnduced ACTH Secretion
Authors: Takao Toshihiro , Hashimoto Kozo , Hirasawa Ryuto , Makino Shinya , Sugawara Masanori , Murakami Kazuharu , Ota Zensuke
Published: September 2006

Plasma ACTH increased after an intra‐third ventricular administration of noradrenaline (NA). An iv corticotrophin‐releasing factor (CRF) antagonist [alpha‐helical CRF(9–41)] injection did not affect ACTH secretion by itself, whereas it significantly reduced NA‐induced ACTH secretion. These results suggest that NA centrally stimulated ACTH secretion and that endogenous CRF is involved in this ACTH secretion.
Switching Between Two Types of Bursting Activity of Single Ca+2‐Activated K+ Channels in Dissociated Neurons
Authors: Yamamoto D. , Pinnock R. D. , Sattelle D. B.
Published: September 2006

Single channel recordings of Ca2+‐activated K+ currents were made from dissociated cockroach neurons by means of the gigaohm‐seal patch‐clamp technique. Bursts of single channel openings were composed of two distinct classes: the ‘long‐open burst’ contained groups of long, rectangular, pulse‐like openings with durations of 3.5 to 1.2 ms (depending on membrane potential), whereas the ‘flickering burst’ consisted of clusters of brief openings with an average duration of 0.4 ms (voltage‐independent) separated by short closings with a duration of about 1.0 ms. The long‐open burst and the flickering burst appeared to reflect distinct states of a single Ca2+‐activated K+ channel because direct transitions between these two types of burst were often detected. We present a kinetic scheme for the gating activation pathway of a neuronal Ca2+‐activated K+ channel, based on these findings.
The Hypothalamic Origin of an Insulin Secretion Promoting Factor Present in the Plasma of Normal Rats
Authors: Bobbioni‐Harsch Elisabetta , Jeanrenaud Bernard
Published: September 2006

Hypothalamic and plasma extracts from normal rats both contain a factor whose property is to stimulate insulin secretion. The two factors have many characteristics in common. Both are active in vivo (when administered to normal recipient rats) and in vitro (when infused into perfused rat pancreases). Both are inactivated by HCI hydrolysis. Both elute at the same ratio between elution volume of the peaks and void volume after gel‐chromatographies are carried out, first on Sephadex G‐50, then on Biogel P‐2, indicating that they have a similar molecular weight which ranges between 800 and 1,200 Daltons. When anaesthetized rats are submitted to an acute bilateral electrical stimulation of the lateral hypothalamus, the insulin secretion stimulating activity present in the plasma is enhanced compared to that measured in sham‐stimulated control rats. Conversely, the insulin secretion promoting activity is decreased in plasma from rats whose ventral hypothalamus is acutely and electrolytically lesioned. These data indicate that, in normal rats, the hypothalamus contains an insulin secretion promoting factor that is releasable in the plasma.
Combined Autoradiographic and Immunohistochemical Evidence for an Association of Somatostatin Binding Sites with Growth Hormone‐Releasing Factor‐Containing Nerve Cell Bodies in the Rat Arcuate Nucleus
Authors: Epelbaum J. , Moyse E. , Tannenbaum G. S. , Kordon C. , Beaudet A.
Published: September 2006

The regulation of growth hormone secretion depends upon the complex interplay between two hypothalamic hypophysiotropic factors: growth hormone‐releasing factor and somatotropin release inhibiting factor or somatostatin. Interactions between these two neurohormones appear to be exerted both distally, at the level of pituitary somatotropes, and proximally, within the hypothalamus. In an attempt to detect a possible anatomical substrate for central interactions between the two neurohormones, we compared the autoradiographic distribution of specifically labeled somatostatin binding sites with the immunohistochemical distribution of growth hormone‐releasing factor‐containing neurons in the hypothalamus of adult rats. Somatostatin binding sites were labeled in vitro by incubating serial brain sections with [125l]TyrO‐DTrp8‐somatostatin. Growth hormone‐releasing factor‐immunoreactive neurons were visualized in a second set of animals, using an antiserum raised against synthetic rat growth hormone‐releasing factor (1–29) NH2. In light microscopic autoradiograms of sections incubated with [125l]somatostatin the label was found to be concentrated over small, round or oval neuronal perikarya clustered within the ventrolateral aspect of the arcuate nucleus. The topographic distribution of these [125l]somatostatin‐labeled cells was similar to that of growth hormone‐releasing factor‐immunoreactive neurons detected within the same region. Moreover, the number of [125l]somatostatin‐labeled cells was found to vary in parallel with that of growth hormone‐releasing factor‐immunoreactive neurons throughout the rostro‐caudal extent of the arcuate nucleus (coefficient of correlation r = 0.80). These results suggest that somatostatin binding sites may be directly associated with the perikarya of arcuate growth hormone‐releasing factor neurons. Such an association would provide an anatomical substrate for a direct regulation of growth hormone‐releasing factor secretion by somatostatin at the hypothalamic level.
Stimulation of Alpha‐Adrenoceptors Facilitates the Release of Growth Hormone‐Releasing Hormone from Rat Hypothalamus in vitro
Authors: Tsagarakis S. , Ge Feng , Rees L. H. , Besser G. M. , Grossman A.
Published: September 2006

While extensive evidence suggests that adrenoceptors play an important role in the control of growth hormone in the rat, there are few studies involving the direct measurement of growth hormone‐releasing hormone (GHRH). We have therefore developed a radioimmunoassay for rat GHRH, and used it to investigate the modulation of GHRH release by noradrenaline from incubated rat hypothalamus in vitro. The GHRH radioimmunoassay had no significant cross‐reactivity with other hypothalamic or GHRH‐related peptides, and was sensitive to 4 pg/tube; intra‐ and interassay coefficients of variation were 6% and 12% respectively. Single incubated rat hypothalami produced a stable and readily measurable output of GHRH in successive 20 min incubations after an initial 60 min preincubation; the release of GHRH was increased in the presence of 56 mM KCI, but did not respond to KCI‐depolarization when calcium was excluded from the medium. Stimulated GHRH release was identical to synthetic rat GHRH(1–43) on high‐performance liquid chromatography and Sephadex G‐75 chromatography.

Noradrenaline stimulated GHRH secretion in a dose‐dependent manner in the concentration range 10−10— 10−6M, with a plateau in response at 10−7M. Stimulation with noradrenaline 10−7M was blocked by idazoxan 10−5M and attenuated by thymoxamine 10−5M, but was unaffected by timolol 10−5M. Both the α2‐adrenoceptor agonist guanfacine, and the α1‐adrenoceptor agonist methoxamine, specifically stimulated GHRH secretion.

It is concluded that noradrenaline stimulates the release of GHRH at both α1 and α2‐adrenoceptors.
Effect of Sex, Intrauterine Position and Androgen Manipulation on the Development of Brain Aromatase Activity in Fetal Ferrets
Authors: Krohmer Randolph W. , Baum Michael J.
Published: September 2006

Experiments were conducted to explore the possible relationship between testicular androgen secretion and the development of brain aromatase activity in fetal ferrets. Aromatase activity in the preoptic+mediobasal hypothalamus and temporal lobe was similar in fetuses of both sexes between embryonic Days 26 and 36 even though whole body androgen content was invariably higher in males than females. Whole body androgen content was significantly higher in females located caudally (downstream) from two or more as opposed to zero or one males in the same uterine horn; nevertheless their brain aromatase activity was similar. Finally, maternal treatment with either the androgen receptor antagonist Flutamide or 5α‐dihydrotestosterone propionate beginning on gestational Day 24 did not affect brain aromatase activity in fetal offspring of either sex, delivered on embryonic Day 34. Previous studies suggest that the biosynthesis of estrogen in the fetal ferret brain is normally greater in males than females. The present results suggest that this sex difference results primarily from increased androgenic substrate being available to non‐saturated aromatizing enzymes and not from an androgen‐dependent activation of aromatase.
Release of Atrial Natriuretic Factor from Intact and Hypophysectomized Rat Hypothalamic Expiants
Authors: Nissen R. , Gutkowska J. , Renaud L. P.
Published: September 2006

Experiments examined release of atrial natriuretic factor (ANF), measured by radioimmunoassay, from acutely prepared explants of rat hypothalamus maintained in vitro by intra‐arterial perfusion of artificial cerebrospinal fluid. Perfusates collected from intact preparations contained 6.1 ± 0.6 pg (mean ± SEM) of ANF per 2‐min sample. Following a 3‐min infusion of noradrenaline (60 μM), ANF release increased significantly (P<0.05) to 11.4±1.4 pg/sample. Media collected from hypophysectomized preparations showed the same basal ANF release (6.8 ± 0.9 pg/sample) as intact preparations, but demonstrated no significant increase after noradrenaline infusions. Levels of spontaneous ANF release were not appreciably affected by the absence of the paraventricular nuclei and/or the anteroventral third ventricle area.

Extracted material from the perfusate by reverse‐phase high performance liquid chromatography revealed two main peaks of immunoreactive ANF: a small molecular weight form that coeluted with synthetic ANF (99–126) and with similar biological activity in a radioreceptor assay, and a larger molecular weight form with the same elution profile as the ANF (1–126) prohormone.

These observations indicate that the ANF released from perfused rat hypothalamic explants contains distinct contributions from the hypothalamus (sites undetermined) and the neurointermediate lobe.
Melatonin Receptor Sites in the Syrian Hamster Brain and Pituitary. Localization and Characterization Using [125|]lodomelatonin*
Authors: Williams L. M. , Morgan P. J. , Hastings M. H. , Lawson W. , Davidson G. , Howell H. E.
Published: September 2006

A high‐affinity, discretely localized melatonin receptor has been characterized and mapped within the brain and pituitary of the Syrian hamster using the high specific activity ligand [125|]iodomelatonin and a combination of in vitro autoradiography and membrane homogenate receptor assays. Specific binding of radioligand was found in regions of the epithalamus and hypothalamus in the brain and the pars tuberalis of the pituitary. Excitatory amino‐acid lesions destroyed [125|]iodomelatonin binding within the brain, demonstrating that binding sites are located on neurons. Analysis of [125|]iodomelatonin binding to membrane homogenates of the pars tuberalis revealed a linear relationship between specific ligand binding and the amount of tissue. The time‐course of specific binding at 37°C reached equilibrium after 30 min and remained stable thereafter. The addition of increasing concentrations of [125|]iodomelatonin alone and in the presence of 1 μM melatonin showed that specific binding reached equilibrium at 80 to 100 pM. Analysis of the saturation isotherm using a one‐site binding model was consistent with a single receptor site with a Kd of 29.3 (±5.9 SEM) pM and Bmax of 2.54 (±0.19 SEM) fmol/mg protein.
Somatostatin and Thyrotrophin‐Releasing Hormone Response and Receptor Status of a Thyrotrophin‐Secreting Pituitary Adenoma: Clinical and in vitro Studies
Authors: Levy Andrew , Eckland David J. A. , Gurney Alison M. , Reubi Jean‐Claude , Doshi Rasikbala , Lightman Stafford L.
Published: September 2006

We have described a patient with a thyrotrophin‐secreting pituitary adenoma and correlated a detailed physiological and anatomical investigation of the surgically resected tumour with its in vivo regulation. Thyrotrophin secretion was inhibited by circulating thyroid hormones, dopaminergic agonists and the somatostatin analogue SMS 201–995 but could not be stimulated by thyrotrophin‐releasing hormone or further inhibited by exogenous triiodothyronine. Prolonged treatment with SMS 201–995 caused tumour shrinkage as shown by successive computed tomography scans but was accompanied by tumour desensitization and the development of diabetes mellitus. This is the first thyrotroph adenoma in which somatostatin receptors have been directly demonstrated and shown to completely block thyrotrophin‐releasing hormone‐induced inositol phospholipid accumulation when occupied. In addition, preincubation with triiodothyronine significantly inhibited thyrotrophin‐releasing hormone‐induced inositol phospholipid turnover in dispersed pituitary cells indicating that in this tumour, circulating thyroid hormones were exerting feedback inhibition at the level of the pituitary either by reducing the number of thyrotrophin‐releasing hormone receptors and/or their coupling to second messenger pathways. In keeping with this hypothesis, the acute reduction in intrapituitary triiodothyronine by sodium ipodate in vivo had no effect on peripheral thyrotrophin over 6 h suggesting that the onset of the effect of triiodothyronine withdrawal on thyrotrophin secretion was suitably delayed. The importance of the inositol phospholipid second messenger pathway in transducing the secretory response in this tumour was further corroborated by electrophysiological studies which demonstrated thyrotrophin‐releasing hormone‐induced changes in K+ currents which are dependent on intracellular Ca2+ ions, presumably mobilized via the inositol phospholipids. In addition to thyrotrophin and α subunit, growth hormone mRNA and growth hormone were found throughout the tumour as were two populations of cells distinguished electron microscopically by the size of their secretory granules. Although acromegalic features are not unusual in thyrotroph adenomas, our patient showed no evidence of inappropriate growth hormone secretion during surgery or in response to pre‐ or post‐operative insulin stress tests.
A Small Population of Tyrosine Hydroxylase‐lmmunoreactive Neurons in the Guinea‐Pig Arcuate Nucleus Contains Progestin Receptor‐lmmunoreactivity
Authors: Blaustein Jeffrey D. , Turcotte Joanne C.
Published: September 2006

We studied the co‐localization of progestin receptor‐immunoreactive (PR‐IR) cell nuclei and tyrosine hydroxylase‐immunoreactive (TH‐IR) cell bodies in guinea‐pig brain with a double antibody, immunocytochemical technique. Sections were first immunostained for estradiol‐induced PR‐IR using a peroxidase‐antiperoxidase technique with diaminobenzidine as the chromogen followed by α‐naphthol as the chromogen for TH‐IR. We examined the periventricular‐preoptic area and the arcuate nucleus, because these two sites are dense in both PR‐IR cells and TH‐IR cells (cell groups A14 and A12, respectively), and the dorsal hypothalamic Area A13, because this area contains a high density of TH‐IR cells, but few PR‐IR cells. No co‐localization was seen in the periventricular‐preoptic area or Area A13. However, a small proportion (5% to 13%) of TH‐IR cells in the arcuate nucleus was observed to have PR‐IR cell nuclei with the rostral arcuate showing the greatest concentration of co‐localized cells. In order to determine if the estradiol pretreatment required to induce PR‐IR influenced TH‐IR, TH‐IR in estradiol‐primed guinea‐pigs was compared with that of vehicle‐injected controls. This treatment did not noticeably influence the amount of TH‐IR in the arcuate nucleus. Therefore, the results of these experiments suggest that, although some of the TH‐IR neurons in the arcuate nucleus contain PR‐IR, this relationship is seen in less than 15% of the TH‐IR cells. In many cases, PR‐IR neurons were found to have TH‐IR varicosities closely associated with their cell bodies.
Spinal Arginine Vasopressin Elevates Renal Nerve Activity in the Rat
Authors: Riphagen Colleen L. , Pittman Quentin J.
Published: September 2006

Intrathecal injections of arginine vasopressin increased activity recorded from multifiber renal nerve bundles of anesthetized rats by 47 + 14%. This response was significantly attenuated following perfusion of the intrathecal space with a vasopressin antagonist, d(CH2)5Tyr(Me)AVP. It is unlikely that vasopressin leaked to the periphery as iv administration of 10 pmol vasopressin decreased renal nerve activity by 9 + 1%. Electrical stimulation of the paraventricular nucleus (three stimuli at 20 to 100 μA, 100 or 200 Hz) caused a biphasic excitatory response with the peaks of increased renal nerve activity occurring between 50 to 100 and 100 to 200 ms after stimulation. Intrathecal application of the vasopressin antagonist prior to repeating the stimulation of the paraventricular nucleus attenuated the second excitatory response without affecting the first excitatory episode. In animals in which the stimulating electrode was located adjacent to, but not within, the paraventricular nucleus, a monophasic excitatory response (at between 100 to 150 ms after the stimulation) was observed. This response was not attenuated by the intrathecal antagonist. These results are consistent with earlier studies which suggested that arginine vasopressin may function as a mediator of synaptic transmission at spinal levels in pathways influencing kidney function.
Stress‐Related Changes in β‐Endorphin Processing: The Limitations of Slaughterhouse Material
Authors: Smith A. Ian , Wallace Catherine A. , Clarke Lain J. , Funder John W.
Published: September 2006

In the sheep, unlike many other species, a significant proportion (>25%) of immunoreactive β‐endorphin in the anterior pituitary is post‐translationally modified to opioid‐inactive, α‐N‐acetylated forms. In a study to determine the precise molecular nature of α‐N‐acetylated β‐endorphin immunoreactivity, we noted a striking difference in high‐performance liquid chromatography profiles of anterior pituitary extracts between sheep killed on the farm, and age‐, sex‐ and strain‐matched slaughterhouse animals. These altered patterns of a‐N‐acetylated β‐endorphin processing were reproduced in farm animals by chronic (≤ 4 days) treatment with the synthetic glucocorticoid dexamethasone; in contrast dexamethasone had no effect on a‐N‐acetylated β‐endorphin processing in hypothalamo‐pituitary disconnected sheep. These data suggest that (1) the change in processing is a stress response, mediated by prolonged glucocorticoid exposure, (2) this effect is central, rather than a direct effect on the pituitary, and (3) the relative abundance of various peptide sequences in slaughterhouse‐derived material may not reflect their abundance under more physiological conditions.