Canonical transient receptor potential (TRPC) channels are a family of non-selective cation channels that play a crucial role in modulating neuronal excitability due to their involvement in intracellular Ca2+ regulation and dendritic growth. TRPC5 channels a) are one of the two most prevalent TRPC channels in the adult rodent brain; b) are densely expressed in deep layer pyramidal neurons of the prefrontal cortex (PFC); and c) modulate neuronal persistent activity necessary for working memory and attention. In order to evaluate the causal role of TRPC5 in motivation/reward-related behaviors, conditional forebrain TRPC5 knock-down (trpc5-KD) mice were generated and trained to nose-poke for intravenous cocaine. Here we present a data set containing the first 6 days of saline or cocaine self-administration in wild type (WT) and trpc5-KD mice. In addition, we also present a data set showing the dose-response to cocaine after both groups had achieved similar levels of cocaine self-administration. Compared to WT mice, trpc5-KD mice exhibited an apparent increase in self-administration on the first day of cocaine testing without prior operant training. There were no apparent differences between WT and trpc5-KD mice for saline responding on the first day of training. Both groups showed similar dose-response sensitivity to cocaine after several days of achieving similar levels of cocaine intake.

Shyness and social anxiety are predominant features of some psychiatric disorders including autism, schizophrenia, anxiety and depression. Understanding the cellular and molecular determinants of sociability may reveal therapeutic approaches to treat individuals with these disorders and improve their quality of life. Previous experiments from our laboratory have identified selective mRNA and protein expression of a nonselective cation channel known as the canonical transient receptor potential channel 4 (TRPC4s) in brain regions implicated in emotional regulation and anxiety. TRPC4 is highly expressed in the corticolimbic regions of the mammalian brain. We hypothesized that robust corticolimbic expression of TRPC4 may regulate the brain’s response to emotion and anxiety resulting in changes in social interaction. Here we test trpc4 gene knockout rats in a model of social anxiety/interaction. We found that the Trpc4 knockout animals spent significantly less time exploring a juvenile intruder rat compared to their wild-type counterparts and Sprague-Dawley (SD) rats. Furthermore, Trpc4 wild-type (Fisher 344) rats explored the juvenile significantly less than the SD rats. These findings indicate that the trpc4 gene plays a role in modulating cellular excitability in specific regions of the brain associated sociality and/or anxiety.

Abstract:Here we describe the first report of using low-cost cellular or web-based digital cameras to image and quantify standardized rapid immunoassay strips as a new point-of-care diagnostic and forensics tool with health applications. Quantitative ratiometric pixel density analysis (QRPDA) is an automated method requiring end-users to utilize inexpensive (∼ $1 USD/each) immunotest strips, a commonly available web or mobile phone camera or scanner, and internet or cellular service. A model is described whereby a central computer server and freely available IMAGEJ image analysis software records and analyzes the incoming image data with time-stamp and geo-tag information and performs the QRPDA using custom JAVA based macros (http://www.neurocloud.org). To demonstrate QRPDA we developed a standardized method using rapid immunotest strips directed against cocaine and its major metabolite, benzoylecgonine. Images from standardized samples were acquired using several devices, including a mobile phone camera, web cam, and scanner. We performed image analysis of three brands of commercially available dye-conjugated anti-cocaine/benzoylecgonine (COC/ BE) antibody test strips in response to three different series of cocaine concentrations ranging from 0.1 to 300 ng/ml and BE concentrations ranging from 0.003 to 0.1 ng/ml. This data was then used to create standard curves to allow quantification of COC/BE in biological samples. Across all devices, QRPDA quantification of COC and BE proved to be a sensitive, economical, and faster alternative to more costly methods, such as gas chromatography-mass spectrometry, tandem mass spectrometry, or high pressure liquid chromatography. The limit of detection was determined to be between 0.1 and 5 ng/ml. To simulate conditions in the field, QRPDA was found to be robust under a variety of image acquisition and testing conditions that varied temperature, lighting, resolution, magnification and concentrations of biological fluid in a sample. To determine the effectiveness of the QRPDA method for quantifying cocaine in biological samples, mice were injected with a sub-locomotor activating dose of cocaine (5 mg/kg; i.p.) and were found to have detectable levels of COC/BE in their urine (160.6 ng/ml) and blood plasma (8.1 ng/ml) after 15-30 minutes. By comparison rats self-administering cocaine in a 4 hour session obtained a final BE blood plasma level of 910 ng/ml with an average of 62.5 infusions. It is concluded that automated QRPDA is a low-cost, rapid and highly sensitive method for the detection of COC/BE with health, forensics, and bioinformatics application and the potential to be used with other rapid immunotest strips directed at several other targets. Thus, this report serves as a general reference and method describing the use of image analysis of lateral flow rapid test strips.

The canonical transient receptor potential (TRPC) family of Ca 2+ permeable, non-selective cation channels is abundantly expressed throughout the brain, and plays a pivotal role in modulating cellular excitability. Unlike other TRPC channels, TRPC4 subtype expression in the adult rodent brain is restricted to a network of structures that receive dopaminergic innervation, suggesting an association with motivation- and reward-related behaviors. We hypothesized that these channels may play a critical role in dopamine-dependent drug-seeking behaviors. Here, we gathered data testing trpc4 knockout (KO) rats and wild-type (WT) littermates in the acquisition of a natural sucrose reward (10 days), and cocaine self-administration (13 days) at 0.5 mg/kg/infusion. Rats lacking the trpc4 gene ( trpc4-KO) learned to lever press for sucrose to a similar degree as their WT controls. However, when they were switched to cocaine, the trpc4-KO rats had substantially reduced cocaine-paired lever pressing compared to WT controls. No obvious group differences in inactive lever pressing were observed, for any time, during cocaine self-administration.

Brief Report neuroscienceThis study examines the role of the canonical transient receptor potential channel 4 (TRPC4) in regulating social interaction behavior using rats lacking the trpc4 gene. We have previously found TRPC4 mRNA to be predominantly expressed in brain regions associated with memory, motivation, stress and anxiety 1,2 . Furthermore, TRPCs have been suggested to be important cation channels involved in modulating cellular excitability. To establish a role for TRPC4 channels in social behavior, we knocked out the trpc4 gene using the Sleeping Beauty transposon gene trap system and measured social interaction. We hypothesized that trpc4 gene deletion would disrupt social interaction in the knockout rats compared to their wild-type controls. In addition, we examined whether the wild-type (Fisher 344) strain differed from the Sprague-Dawley (SD) strain. RESULTS TRPC4 Knock-out RatsThe Sleeping Beauty (SB) gene-trap transposon method was used to create the Trpc4 knock-out animals 4 . The SB method uses cut-and-paste transposable elements to generate heritable loss-of-function mutations. Figure 1a shows the location of the trpc4 gene on the rat genome and where the transposon was inserted. By inserting the SB transposon into the first intron of the trpc4 gene, the full-length protein product is completely eliminated. Using primers for the Trpc4 knock-out and wildtype alleles, we were able to confirm the deletion using PCR and gel electrophoresis (Fig 1b). Social Exploration TrialsSocial interaction tests were developed 25 years ago and have since been reliable in assessing anxiety-like behaviors in rats and mice 5 . On average, healthy naïve rats will explore for about 80 seconds per 3-minute trial 1 . Results from our social exploration trials (Fig. 2a) show that Trpc4 knock-out rats exhibited the least amount of exploratory behaviors with a mean exploration time of 54 seconds. This is significantly less than Trpc4 wild-type rats, who explored for 81.63 seconds on average, and SD rats, with a mean exploration time of 93.19 sec. Additionally, the mean exploration time of Trpc4 wild-type rats is significantly less than the SD rats. Ethidium bromidestained agarose gel visualizing the 905 bp marker for the WT allele and the 510 bp marker for the trpc4 KO allele. To genotype the animals, a 1.5% agarose gel electrophoresis was used.