Navigation Links
News tips from the Journal of Neuroscience

Spontaneous Astrocytic Ca2+ Oscillations and Neurite Growth
Kazunori Kanemaru, Yohei Okubo, Kenzo Hirose, and Masamitsu Iino

This week, Kanemaru et al. explore the signaling pathway between spontaneous Ca2+ oscillations in cultured astrocytes and the promotion of neurite growth. Their results reveal a role for the membrane-bound adhesion molecule N-cadherin. The authors blocked Ca2+ oscillations by preventing IP3 signaling with retroviral-mediated expression of IP3 5-phosphatase (5ppase). This molecule hydrolyzes IP3 and thus prevented spontaneous astrocytic Ca2+ oscillations. Growth cone motility was compromised in hippocampal neurons cultured with 5ppase-expressing astrocytes. Interference with neurotransmitter-evoked astrocytic Ca2+ transients did not affect neurite outgrowth. The messenger was not diffusible because direct contact with an astrocyte deficient in spontaneous Ca2+ signaling arrested growth cone advancement. Surface expression of the growth-promoting molecule N-cadherin was downregulated in 5ppase-expressing astrocytes, and neuronal growth cone advancement was rescued by extrinsic expression of N-cadherin on astrocytes.

Forming Filopodia
Yutaka Furutani, Hitomi Matsuno, Miwa Kawasaki, Takehiko Sasaki, Kensaku Mori, and Yoshihiro Yoshihara

Before synapses form between axons and dendrites, even before dendritic spines take shape, dendritic filopodia are out there, poking and prodding and exploring their surroundings. In this weeks Journal, Furutani et al. searched for intracellular binding partners for telencephalin (TLCN), atelencephalon- and dendrite-specific cell adhesion molecule that is expressed in filopodia. A yeast two-hybrid screen revealed interactions with ezrin, radixin, and moesin of the so-called ERM family; these adaptors link membrane proteins to the actin cytoskeleton. The binding of the cytoplasmic domain of TLCN to ERMs was confirmed using surface plasmon resonance analysis of direct proteinproteininteractions. Phosphorylated ERM proteins colocalized with TLCN in filopodia, but not spines, and contributed to filopodial formation. Reduction of ERM protein expression by small interfering RNA decreased the density and length of filopodia while accelerating spine maturation, whereas ectopic expression of constitutively active ezrin induced the formation of dendritic filopodia.

KisspeptinGPR54 Signaling in Sexual Differentiation
Alexander S. Kauffman, Jin Ho Park, Anika A. McPhie-Lalmansingh, Michelle L. Gottsch, Cristian Bodo, John G. Hohmann, Maria N. Pavlova, Alex D. Rohde, Donald K. Clifton, Robert A. Steiner, and Emilie F. Rissman

Long before their role during puberty and adulthood becomes manifest, gonadal hormones exert influence on the development of sexual dimorphism in the brain. This week, Kauffman et al. examined the role of GPR54, a G-protein-coupled membrane receptor for kisspeptin, in the development of sexually dimorphic traits. Gonadotropin-releasing hormone (GnRH) neurons were activated and released leutinizing hormone after treatment with kisspeptin in wild-type male mice but not in micelacking GPR54. GPR54- deficient males showed the expected male sexual behavior after treatment with testosterone, but they lacked preference for estrous females on olfactory-mediated partner preference behavior. In the anteroventral periventricular nucleus, asexually dimorphic structure where there are more tyrosine hydroxylaseand Kiss1-expressing neurons in females than males, GPR54-deficient males had a female phenotype. They also had reduced motoneurons in the spinal nucleus of the bulbocavernosus, another sexually dimorphic structure. Thus, kisspeptinGPR54 signaling is required for sexually dimorphic development but not for sexual behavior per se.

Mapping the Regulation of Negative Moods
Tom Johnstone, Carien M. van Reekum, Heather L. Urry, Ned H. Kalin, and Richard J. Davidson

This week, Johnstone et al. take the position that everyone has blue moods, but the failure to effectively regulate those moods might underlie susceptibility to major depressive disorder. The authors used functional magnetic resonance imaging to map the patterns of brain activation in depressed and nondepressed subjects as they viewed a standard set of emotionally positive or negative pictures. In order to decrease the associated emotion, subjects were instructed to imagine, for example, a happy out come for a negative image. Pupil dilation provided a measure of arousal. During the reappraisal, nondepressed subjects showed increased activity in the left prefrontal cortex (PFC), whereas depressed subjects showed bilateral increases, indicating greater recruitment of right PFC in the depressed subjects. Control subjects with the highest ventromedial pre-frontal cortex (VMPFC) activation during reappraisal showed less activation in the amygdala, whereas amygdalar activation increased with greater VMPFC activity in depressed subjects.

Contact: Sara Harris
Society for Neuroscience

Related biology news :

1. UCLA Study Shows One-Third of Drug Ads in Medical Journals Do Not Contain References Supporting Medical Claims
2. Recent breakthroughs in common adult leukemia highlighted in New England Journal of Medicine
3. Leukemia Drug Breakthrough Study In New England Journal Of Medicine
4. Open Access journals get impressive impact factors
5. Funding and bureaucracy, not access to journals, are chief obstacles to scientific productivity
6. New journal article urges use of animal serum-free media for growing live cells
7. Impressive new Impact Factors for BioMed Centrals open-access journals
8. Public Library of Science to launch new, open access journal on neglected tropical diseases
9. Are journal rankings distorting science?
10. NIH neuroscience microarray consortium launches high-throughput genotyping services
Post Your Comments:
(Date:11/19/2015)... -- Although some 350 companies are actively involved in molecular ... according to Kalorama Information. These include Roche Diagnostics, Hologic, Abbott ... of the 6.1 billion-dollar molecular testing market, according to ... Diagnostic s .    ... one company and only a handful of companies can ...
(Date:11/17/2015)... Paris , qui ... Paris , qui s,est tenu du ... leader de l,innovation biométrique, a inventé le premier scanner ... sur la même surface de balayage. Jusqu,ici, deux scanners ... les empreintes digitales. Désormais, un seul scanner est en ...
(Date:11/12/2015)... Nov. 12, 2015  A golden retriever that stayed ... dystrophy (DMD) has provided a new lead for treating ... the Broad Institute of MIT and Harvard and the ... . Cell, pinpoints a protective ... the disease,s effects. The Boston Children,s lab of ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... Studies reveal the differences in ... pave the way for more effective treatment for one of ...   --> --> Gum ... in cats, yet relatively little was understood about the bacteria ... been conducted by researchers from the WALTHAM Centre for Pet ...
(Date:11/25/2015)... , Nov. 25, 2015 Orexigen® Therapeutics, ... will participate in a fireside chat discussion at the ... New York . The discussion is scheduled for ... .  A replay will be available ... Contact:McDavid Stilwell  , Julie NormartVP, Corporate Communications and ...
(Date:11/24/2015)... 2015 Cepheid (NASDAQ: CPHD ) today ... following conference, and invited investors to participate via webcast. ...      Tuesday, December 1, 2015 at 11.00 a.m. Eastern Time ...      Tuesday, December 1, 2015 at 11.00 a.m. Eastern Time ... New York, NY      Tuesday, December 1, 2015 ...
(Date:11/24/2015)... - Aeterna Zentaris Inc. (NASDAQ:  AEZS) (TSX: AEZ) (the "Company"), ... Toronto Stock Exchange, confirms that as of the date ... that would cause the recent movements in the Company,s ... About Aeterna Zentaris Inc. . ... Zentaris is a specialty biopharmaceutical company engaged in developing ...
Breaking Biology Technology: