Growth retardation and altered autonomic control in mice lacking brain serotonin

Tue, 16 Jun 2009 09:41:30 -0500

Haploinsufficiency for Pten and Serotonin transporter cooperatively influences brain size and social behavior

Mon, 9 Mar 2009 15:32:56 -0500

A robust automated system elucidates mouse home cage behavior structure

Mon, 2 Mar 2009 15:53:14 -0600

Goulding EH, Schenk AK, Juneja P, MacKay AW, Wade JM, Tecott LH

Recommended by Randy Blakely

This paper demonstrates the power of home cage behavior monitoring studies of genetically variant mice, with particular reference to changes in activity/feeding of 5HT2C receptor KO mice

Keywords: circadian | ingestion | obesity | phenotyping | 5HT2C receptor | 2C mice |

Link to abstract and full article: PNAS, 2008 Dec 30; 105(52): 20575-82

Axonal projections originating from raphe serotonergic neurons in the developing and adult zebrafish, danio rerio, using transgenics to visualize raphe-specific pet1 expression

Thu, 5 Feb 2009 11:21:05 -0600

Lillesaar C, Stigloher C, Tannhauser B, Wullimann MF, Bally-Cuif L.

Recommended by Alex Bonnin

The authors characterized regulatory elements of the zebrafish raphe-specific gene pet1 and used them to generate a pet1-eGFP transgenic zebrafish line. They combined the analysis of GFP+ axons and retrograde tracing studies to describe in detail the projection patterns and anatomical distribution of serotonergic cells in the zebrafish brain. Similarities and differences with mammalian serotonergic projection patterns are described in detail. Interestingly, the authors identify a new population of serotonergic cells in the ventrolateral hindbrain which has no equivalent in the mammalian brain. These observations are discussed and suggested that some functions executed exclusively by neurons of the raphe subnuclei in mammals may be spread over more widely distributed serotonergic neurons throughout the zebrafish brain.

Keywords: serotonin | raphe | pet1 | 5-HT | green fluorescent protein |

Link to abstract and full article: The Journal of Comparative Neurology, Volume 512 (2): 158-182

Identification of a CREB-dependent serotonergic pathway and neuronal circuit regulating foraging behavior in caneorhabditis elegans: a useful model for mental disorders and their treatments?

Tue, 3 Feb 2009 17:11:23 -0600

Zubenko GS, Jones ML, Estevez AO, Huges HB III, Estevez M

Recommended by Randy Blakely

In the category of “something borrowed, something blue,” Zubenko and coworkers describe a pathway in C. elegans that utilizes serotonin acquired from other neurons to regulate foraging behavior. Similarities to borrowed serotonin in the thalamocortical pathway in mammals makes this interesting reading . . .

Keywords: serotonin | CREB | animal model | brain | behavior | major depression |antidepressant | C. elegans

Link to abstract and full article: Am J Med Genet B Neuropsychiatr Genet 2008 Nov 25; 150B(1):12-23

Excess of serotonin affects embryonic interneuron migration through activation of the serotonin receptor 6

Tue, 3 Feb 2009 16:53:53 -0600

Riccio O, Potter G, Walzer C, Vallet P, Szabo G, Vutskits L, Kiss JZ, Gayer AG

Recommended by Gregg Stanwood

This paper provides an intriguing demonstration of previously unrecognized effects of serotonin on the rate of interneuron migration during forebrain development. This work raises many new ideas and questions for translational investigation.

Keywords: 5HT | serotonin | major depression | interneuron | migration | development | GAD65 | 5HT6 receptors

Link to abstract and full article: Molecular Pharmacology advanced online publication, 29 July 2008

Genetic disruption of both tryptophan hydroxylase genes dramatically reduces serotonin and affects behavior in Models Sensitive to antidepressants

Tue, 9 Dec 2008 13:01:00 -0600

Savelieva KV, Zhao S, Pogorelov VM, Rajan I, Yang Q, Cullinan E, Lanthorn TH

Recommended by Alex Bonnin:

This paper describes the generation of ‘serotonin-less’ mice. Genes coding for two enzymes responsible for 5HT biosynthesis in the periphery (TPH1) and in the CNS (TPH2) were both knocked-out in a single mouse line. Measures of 5HT concentrations in the CNS and periphery confirmed that double-knock out (DKO) mice are ‘5HT-less’ but not completely devoid of 5HT: a small but measurable amount of 5HT remains in the CNS and periphery of DKO mice, suggesting the existence of an alternate pathway for 5HT biosynthesis (i.e. through metabolization of tryptophan by phenylalanine hydroxylase; however this pathway is far from being efficient enough to fully compensate for the absence of TPH1/2 in the adult). Surprisingly, DKO mice develop and survive fairly normally (despite a decreased body weight and length). The authors subjected the mice to a battery of behavioral tests which revealed only mild enhancement over the phenotypes observed in TPH2 single-knock out regarding anxiety and depression-related behaviors. This was to be expected since TPH2 is the sole enzyme responsible for 5HT synthesis in the CNS. Curiously DKO don’t suffer from cardiac malfunction, unlike the single TPH1-KO reported earlier (Cote et al., 2003; 2007). Given the importance of 5HT in early embryonic and postnatal development, it is surprising that DKO mice appear to develop normally. However, it should be pointed out that only the ‘gross morphology’ of the brain appears histologically normal (albeit a smaller body weight and size), but no further evidence of proper brain development is provided.

Keywords: 5HT | serotonin | TPH1 | TPH2 | TPH1KO and TPH2KO mice | TPH1/TPH2 DKO mice | behavior |

Link to abstract and full article: PLoS ONE 3(10): e3301 doi:10.1371/journal.pone0003301

Serotonin Transporter transgenic (SERTCRE) mouse line reveals developmental targets of serotonin specific reuptake inhibitors (SSRIs)

Wed, 15 Oct 2008 16:39:50 -0500

Narboux-Nême N, Pavone LM, Avallone L, Zhuang X, Gaspar P

Recommended by Alex Bonnin:

The authors took advantage of recent availability of a SERT-Cre mouse line to investigate the sites of SERT expression in the developing mouse brain. This study confirms and also provides some clarifications about previously described transient expression patterns of SERT in the developing forebrain and some neural crest-derived tissues.

Keywords: 5HTT | serotonin | brain development | recombinase | mouse models | thalamus | cortex | prefrontal | hippocampus | cingulate

Link to abstract and full article: Neuropharmacology 55 (2008) 994-1005

Pharmacological REM Sleep Suppression Paradoxically Improves Rather THan Impairs Skill Memory

Mon, 13 Oct 2008 14:58:34 -0500

How the Serotonin Story is Being Rewritten by New Gene-Based discoveries Principally Related to SLC6A4, the Serotonin Transporter Gene, Which Functions to Influence All Cellular Serotonin systems

Mon, 13 Oct 2008 14:43:58 -0500

Murphy DL, Fox MA, Timpano KR, Moya PR, Ren-Patterson R, Andrews AM, Holmes A, Lesch KP, Wendland JR

Recommended by Ana Carneiro:

Keywords: serotonin transporter | homeostasis | anxiety | obsessive-compulsive disorder | depression | epistasis |

Link to abstract and full article: Neurpharmacology: 55(2008): 932-960

Sustained Effects of Ecstasy on the Human Brain: a prospective neuroimaging study in novel users

Mon, 13 Oct 2008 14:29:53 -0500

Serotonin Hyperinnervation Abolishes Seizure Susceptibility in Otx2 Conditional Mutant Mice

Mon, 15 Sep 2008 15:52:42 -0500

Tripathi PP, Di Giovannantonio LG, Viegi A, Wurst W, Simeone A, Bozzi Y

Recommended by Randy Blakely:

This paper makes an interesting use of a transgenic animal with hyperserotonergic innervation of the forebrain and pharmacological suppression of 5HT synthesis to examine 5HT’s role in seizure susceptibility. Due to changes in DA neurons that also occur in these mice, results may be limited in context but are interesting nonetheless for those interested in traits tracking with elevated serotonergic tone.

Keywords: serotonin transporter | pCPA | kainic acid | hippocampus | seizures | epilepsy | hyperinnervation |

Link to abstract and full article: J. Neurosci, Sept 10, 2008, 28(37): 9271-9276

Gene x Environment Interactions at the Serotonin Transporter Locus

Thu, 14 Aug 2008 11:36:30 -0500

Munafó MR, Durrant C, Lewis G, Flint J

Recommended by David Airey & Clint Canal:

In this meta-analysis, Jonathan Flint and colleagues find a lack of statistical support for serotonin transporter gene by environment interaction. The authors claim that positive results thus far are compatible with chance findings.

Keywords: depression | 5HTTLPR | Gene x Environment interaction | meta-analysis | stressful life events | serotonin transporter |

Targeting of the 5-HT1A Serotonin Receptor to Neuronal Dendrites Is Mediated by Yif1B

Mon, 11 Aug 2008 15:49:47 -0500

Damien Carrel, Justine Masson, Sana Al Awabdh, Catherine Borg Capra, Zsolt Lenkei, Michel Hamon, Michel Boris Emerit and Michéle Darmon

Recommended by Randy Blakely:

Networks of proteins that control 5-HT receptor localization are of keen interest to the research community studying 5-HT signaling, as well as those hunting for novel disease-risk candidate genes. 5-HT1A receptors are important determinants of CNS 5-HT signaling and participate in auto-regulatory control of 5-HT neuron firing. Carrel et al implicated Yif1B as an important determinant of 5HT1A receptor dendritic localization.

Keywords: serotonin transporter | 5HT1a receptor | Yif1B | Dendrite | trafficking | GPCR | intermediate compartment

Link to abstract and full article: J.Neurosci, Aug 6, 2008, 28 (32): 8063-8073

Sporadic Autonomic Dysregulation and Death Associated with Excessive Serotonin Autoinhibition

Wed, 9 Jul 2008 09:35:09 -0500

Audero E, Coppi E, Mlinar B, Rossetti T, Caprioli A, Banchaabouchi MA, Corradetti R, Gross C

Recommended by Randy Blakely:

Audero and colleagues produce and characterize transgenic mice with reversible induction of 5HT1a receptors in raphe neurons (and possibly other sites where serotonin transporters are expressed, such as adrenal, gut, lung and platelets). Results strengthen indications of the importance of serotonin-mediated control of autonomic function but raise a question as to
whether the raphe is truly the critical site of expression for 5HT1A triggered lethality since loss of CNS serotonin neurons in the PET-1 KO does not replicate these findings.

Keywords: serotonin transporter | 5HT1a| | SIDS | Htr1a | serotonin | autoinhibition |

Link to abstract and full article: Science 321, 130 (2008)

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