Determination of transmitter function by neuronal activity

The role of neuronal activity in the determination of transmitter function was studied in cultures of dissociated sympathetic neurons from newborn rat superior cervical ganglia. Cholinergic and adrenergic differentiation were assayed by incubating the cultures with radioactive choline and tyrosine and determining the rate of synthesis and accumulation of labelled acetylcholine and catecholamines. As in previous studies, pure neuronal cultures grown in control medium displayed much lower ratios of acetylcholine synthesis to catecholamine synthesis than did sister cultures grown in medium previously conditioned by incubation on appropriate nonneuronal cells (conditioned medium). However, here we report that neurons treated with the depolarizing agents elevated K+ or veratridine, or stimulated directly with electrical current, either before or during application of conditioned medium, displayed up to 300-fold lower acetylcholine/catecholamine ratios than they would have without depolarization, and thus remained primarily adrenergic. Elevated K+ and veratridine produced this effect on cholinergic differentiation without significantly altering neuronal survival. Because depolarization causes Ca2+ entry in a number of cell types, the effects of several Ca2+ agonists and antagonists were investigated. In the presence of the Ca2+ antagonists D600 or Mg2+, K+ did not prevent the induction of cholinergic properties by conditioned medium. Thus depolarization, either steady or accompanying activity, is one of the factors determining whether cultured sympathetic neurons become adrenergic or cholinergic, and this effect may be mediated by Ca2+

Women\u27s Studies Student Questionnaire

The University of Richmond Women\u27s Studies program developed a student questionnaire in 1996 as part of larger program assessment project from 1993-1996

On the role of cyclic nucleotides in the transmitter choice made by cultured sympathetic neurons

Previous investigations have established that electrical activity or chronic depolarization influences the development of neonatal rat sympathetic neurons in dissociated cell culture. Depolarization reduces their ability to respond to a cholinergic inducing factor produced by non-neuronal cells, allowing normal adrenergic differentiation to proceed (Walicke, P., R. Campenot, and P. Patterson (1977) Proc. Natl. Acad. Sci. U. S. A. 74: 5767–5771). The present study examines whether the developmental effects of depolarization are mediated through cyclic nucleotides. Addition of dibutyryl cAMP, dibutyryl cGMP, adenosine, prostaglandin E1, and cholera toxin all raise neuronal cyclic nucleotide levels and qualitatively mimic the developmental effects of depolarization. However, the quantitative decrease in acetylcholine production caused by these cyclic nucleotide agents is much smaller than that caused by depolarization. Short (48-hr) exposures to the cyclic nucleotide derivatives do not alter transmitter synthesis, indicating that long term developmental changes are involved. Chronic depolarization with elevated K+ increases neuronal cAMP 2-fold but has little effect on cGMP. The increase in cAMP is maintained during several weeks of depolarization and is present as early as the 3rd day in vitro, preceding the significant alterations in adrenergic and cholinergic differentiation. Exposure to 2 mM theophylline also increases neuronal cAMP, but in contrast to the other agents, it enhances cholinergic differentiation. In combination with elevated Ktheophylline further increases neuronal cAMP but still favors cholinergic differentiation. Thus, although cAMP satisfies some criteria for being the second messenger in the developmental effects of depolarization, several findings are consistent with the nucleotide playing a central role: (i) Depolarization has much larger effects on transmitter choice than the cyclic nucleotide agents and (ii) theophylline can uncouple cyclic nucleotide levels from the developmental events

Effects of Sulfates in Water on Performance of Steers Grazing Rangeland

Surface and subsurface water in South Dakota often contains high concentrations of total dissolved solids (TDS) and sulfates, which, in severe cases, can cause livestock deaths. Data from our laboratory have demonstrated that sulfate concentrations of 3,000 ppm in water consumed by steers in dry-lot decreased ADG, feed intake, and water consumption. Little information is available on the effects of water sulfate concentrations on grazing livestock. This study evaluated the effects of water quality and two vegetation communities on the performance of steers grazing rangeland. Eight native pastures at the SDSU Cottonwood Research Station were used. Four pastures were dominated by warm-season shortgrasses (SG) and four by cool-season midgrasses (MG). Yearling steers (105/year) were allotted to pastures in 2001 and in 2002 to attain a moderate stocking rate of 0.50 AUM/acre during a 4-month grazing season. In 2002, cattle were removed after two months due to drought, resulting in a stocking rate of 0.25 AUM/acre. Number of cattle per pasture varied from 7 to 30, depending on pasture size. Cattle in two of the SG and two of the MG pastures received high sulfate water (HS, 2001: average = 3,947 ppm sulfates; 2002: average = 4,654 ppm sulfates) with low sulfate water (LS, 2001: average = 404 ppm sulfates; 2002: average = 441 ppm sulfates) provided in the remaining pastures. Average daily gain was greater for the LS steers than HS steers in 2001 (P = 0.003; 1.85 and 1.65 lb/d, respectively) and in 2002 (P = 0.001; 2.43 and 1.79 lb/d, respectively). An interaction between sulfate concentration in water and vegetation community in 2002 (P = 0.078) resulted from similar ADG for steers on SG (1.83 lb/d) and MG (1.74 lb/d) pastures for HS water, but greater ADG for steers on MG (2.54 lb/d) than SG (2.32 lb/d) pastures for LS water. During the two-year study, only one steer had health problems related to sulfur, with no deaths. Our study showed water with sulfate concentrations of 3,947 ppm and greater reduced ADG of grazing steers, and that the response was influenced by vegetation

The Spread and Utility of Social Network Analysis across a Group of Health Behavior Researchers

Social network analysis (SNA), both as theory and methodology, is a powerful framework for delimiting and studying health behaviors. Using SNA allows scholars to answer new research questions, innovatively investigate the social and systemic contexts of health and behavior, and collaborate on multi- or inter-disciplinary projects. As a result, SNA is growing in popularity within health behavior research and practice. Despite SNA’s contribution and appeal, few health behavior researchers and practitioners have access to formal SNA education; much of the current training efforts occur outside degree-granting curricula. Therefore, the aims of this paper were to: 1) assess the diffusion of SNA, over time, among scholars presenting at AAHB annual meetings; and 2) determine whether AAHB can function as a professional venue for fostering development of SNA-related skills, especially by capitalizing on mentoring relationships. To assess the “spread” of SNA among AAHB scholars, we conducted a network analysis to capture the connections among those presenting research posters between 2016 and 2019. Results indicated sizeable increases in adoption of, and exposure to SNA within this network. Based on these findings, we recommend responding to the growing trends of SNA use by providing conference-based training and education in SNA. We also propose utilizing mentorship ties as leverage points in diffusing SNA within a system of professional scholars and, as a result, advancing health behavior research and practice

What are the barriers and challenges faced by adolescents when searching for sexual health information on the internet? Implications for policy and practice from a qualitative study

Objectives: As sexual health information is increasingly presented digitally, and adolescents are increasingly seeking sexual health information on the internet, it is important to explore the challenges presented by this developing source of information provision. This study examined the key barriers and challenges faced by young people when accessing and using sexual health information online. Methods: A novel qualitative approach was used which combined paired interviews with real-time online activities. A purposive sample of 49 young people aged between 16 and 19 years and diverse in terms of gender, sexuality, religion and socio-demographic background were recruited from areas across Scotland. Data analysis comprised framework analysis of conversational data (including pair interactions), descriptive analysis of observational data, and data integration. Results: This study highlighted practical and socio-cultural barriers to engagement with online sexual health content. Key practical barriers included difficulty filtering overabundant content; limited awareness of specific, relevant, trusted online sources; difficulties in finding locally relevant information about services; and difficulties in navigating large organisations’ websites. Key socio-cultural barriers included fear of being observed; wariness about engaging with visual and auditory content; concern about unintentionally accessing sexually explicit content; and reticence to access sexual health information on social networking platforms or through smartphone applications. These practical and socio-cultural barriers restricted access to information and influenced searching practices. Conclusion: This study provides insights into some of the key barriers faced by young people in accessing and engaging with sexual health information and support online. Reducing such challenges is essential. We highlight the need for sexual health information providers and intervention developers to produce online information that is accurate and accessible; to increase awareness of and promote reliable, accessible sources; and to be sensitive to young people’s concerns about ‘being seen’ accessing sexual health information regarding audio-visual content and platform choice