Kay Colthorpe

Hypothalamic dopamine D1 receptors are involved in the stimulation of prolactin secretion by high environmental temperature in the female sheep

Recent evidence suggests that dopamine, acting via its D1 receptors, may function as a neurotransmitter in intrahypothalamic pathways involved in the stimulation of prolactin secretion. Functional dopamine D1 receptors are present in the ventromedial hypothalamic nucleus (VMH) and we hypothesized that they might be part of a prolactin‐stimulatory pathway activated by stress. We tested this hypothesis in a series of experiments on sheep involving two different forms of stressors, audiovisual (barking dog) and high environmental temperature. We attempted to block the stimulation of prolactin secretion by infusion into the VMH of an antagonist specific for the D1 receptor. Ovariectomised, oestradiol‐implanted merino ewes were surgically implanted with bilateral guide tubes directed at the VMH. After a 180 min pretreatment period, the ewes either were or were not exposed to a stressor (30 min of barking dog or 120 min at 35 °C, 65% relative humidity). D1 receptor antagonist, SCH23390 or vehicle (0.9% saline) was infused into the VMH (1.7 μl/h, 120 nmol/h) for 60 min prior to and during the stressor period. Blood was sampled every 15 min via jugular cannulae and the plasma was assayed for prolactin, cortisol and growth hormone (GH). Both stressors significantly increased prolactin concentrations over control levels. SCH23390 infusion significantly attenuated the prolactin response to high environmental temperature, but had no effect on the prolactin response to audiovisual stress. Cortisol concentrations were significantly increased by audiovisual stress only and were not affected by SCH23390. GH concentrations were not changed by either stressor or infusion. Drug infusion alone did not affect the concentration of the hormones. The data suggest that the VMH D1 receptors are involved in a prolactin stimulatory pathway in response to high environmental temperature. The inability of the D1 antagonist to affect the response to the barking dog indicates that this pathway is stress‐specific, implying that there is more than one mechanism or pathway involved in the prolactin response to different stressors.

A Set of Vertically Integrated Inquiry-Based Practical Curricula that Develop Scientific Thinking Skills for Large Cohorts of Undergraduate Students.

Science graduates require critical thinking skills to deal with the complex problems they will face in their 21st century workplaces. Inquiry-based curricula can provide students with the opportunities to develop such critical thinking skills; however, evidence suggests that an inappropriate level of autonomy provided to underprepared students may not only be daunting to students but also detrimental to their learning. After a major review of the Bachelor of Science, we developed, implemented, and evaluated a series of three vertically integrated courses with inquiry-style laboratory practicals for early-stage undergraduate students in biomedical science. These practical curricula were designed so that students would work with increasing autonomy and ownership of their research projects to develop increasingly advanced scientific thinking and communication skills. Students undertaking the first iteration of these three vertically integrated courses reported learning gains in course content as well as skills in scientific writing, hypothesis construction, experimental design, data analysis, and interpreting results. Students also demonstrated increasing skills in both hypothesis formulation and communication of findings as a result of participating in the inquiry-based curricula and completing the associated practical assessment tasks. Here, we report the specific aspects of the curricula that students reported as having the greatest impact on their learning and the particular elements of hypothesis formulation and communication of findings that were more challenging for students to master. These findings provide important implications for science educators concerned with designing curricula to promote scientific thinking and communication skills alongside content acquisition.

Localization and characterization of dopamine d1 receptors in sheep hypothalamus and striatum

Dopamine receptors are pharmacologically grouped as D1 and D2 receptors. Previous research in the ewe has shown that central D1 receptors may have a role in facilitating prolactin release. The aims of this study were therefore to localize and characterize D1 binding sites in the hypothalamus of sheep. For comparison, a known D1 receptor‐rich tissue (striatum) was also studied. The bioactivities of several D1 analogues were also assessed for their efficacy in sheep tissue. In vitro autoradiography with [125I]‐SCH23982 was used to localize D1 binding sites. The ventromedial hypothalamic nucleus (VMH) displayed moderate levels of specific binding, localized to the medial portion of the nucleus. Low levels of specific binding were seen in the preoptic area, supraoptic nucleus and anterior hypothalamic area. The suprachiasmatic nucleus, median eminence and arcuate nucleus did not show specific binding. As expected the striatum displayed high levels of specific binding. The VMH, preoptic area, median eminence, striatum and anterior pituitary were examined with radioligand binding studies to quantify and characterize D1 binding sites. Scatchard analysis gave KD 1.04 nM and Bmax 127.4 fmol/mg protein for VMH and KD 1.99 nM and Bmax 454.6 fmol/mg protein for striatum. While specific binding occurred in the preoptic area and median eminence this binding did not show saturation characteristics. Specific binding was not observed in the anterior pituitary. Affinities determined by competitive binding studies showed that the binding sites in both VMH and striatum have the characteristics of a D1 receptor, that is, high affinity for the D1 agonists and antagonists, low affinity for dopamine and the serotonergic antagonist ketanserin and extremely low affinity for the D2 agonists and noradrenaline. Adenylate cyclase studies showed that in the striatum dopamine and the D1 agonists, fenoldopam and SKF38393, were able to cause significant dose‐dependent increases in adenylate cyclase activity. In contrast the D1 agonist, SKF82958, was inactive in this system. The D1 antagonists SCH23390 and SCH39166, but not SKF83566, abolished the adenylate cyclase response to 50 μM dopamine. In the VMH the D1 agonist SKF38393, but not dopamine, stimulated adenylate cyclase activity. In conclusion, these results demonstrate that D1 binding sites exist within the hypothalamus in the VMH and that these binding sites have the characteristics of D1 receptors. These receptors are a potential site of action for dopamine in facilitating prolactin release. In addition, the results show that at least for some dopamine analogues, receptor binding affinity does not always correlate with biological activity.

Changes in Biology Self-Efficacy during a First-Year University Course.

Biology self-efficacy was measured in first-year students. Self-efficacy was lower in females than in males, most noticeably in high-achieving students. High school experience contributed to self-efficacy at the beginning of the semester, and this was replaced by progressive grades at the end of the semester. Self-efficacy did not correlate with exam grades.

Are they using my feedback? The extent of students’ feedback use has a large impact on subsequent academic performance

Feedback is known to have a large influence on student learning gains, and the emergence of online tools has greatly enhanced the opportunity for delivering timely, expressive, digital feedback and for investigating its learning impacts. However, to date there have been no large quantitative investigations of the feedback provided by large teams of markers, feedback use by large cohorts of students, nor its impact on students’ academic performance across successive assessment tasks. We have developed an innovative online system to collect large-scale data on digital feedback provision and use. Our markers (n = 38) used both audio and typed feedback modalities extensively, providing 388 ± 4 and 1126 ± 37 words per report for first- and second-year students, respectively. Furthermore, 92% of first year and 85% of second-year students accessed their feedback, with 58% accessing their feedback for over an hour. Lastly, the amount of time students spent interacting with feedback is significantly related to the rate of improvement in subsequent assessment tasks. This study challenges assertions that many students do not collect, or use, their feedback. More importantly, we offer novel insights into the relationships between feedback provision, feedback use and successful academic outcomes.

Learning hindrances and self-regulated learning strategies reported by undergraduate students: identifying characteristics of resilient students

ABSTRACT Students in higher education face a variety of learning hindrances while studying at university. These hindrances may negatively impact on learning by distracting from study, or may enhance learning by encouraging students to address challenges as they arise. In the current study students were asked to describe their learning hindrances at a single point early in semester, and to outline the strategies for overcoming these hindrances in future. Five hindrance clusters were determined and differences between student academic subgroups were identified. Hindrances associated with difficulties understanding were reported most frequently by improving students, who had demonstrated resilience by passing second year biomedical science courses after failing in first year. Improving students were also most likely to report learning strategies that promote understanding. These results suggest that early interventions to encourage students to critically evaluate their understanding may benefit struggling students.

Prompting undergraduate students’ metacognition of learning: implementing ‘meta-learning’ assessment tasks in the biomedical sciences

Abstract To succeed at post-secondary education, it’s essential that students develop an understanding of their own knowledge and learning processes. This metacognition of learning, or ‘meta-learning’, helps students to become more effective learners, as they become more aware of their self-regulatory processes and recognise the effectiveness of their study strategies. To increase biomedical science students’ self-awareness, we have designed and implemented meta-learning assessment tasks across our biomedical science courses. Most students reported that meta-learning tasks had a positive impact on their learning, as they prompted self-regulatory processes of forethought and self-reflection. We found that students were equally likely to change or not change their study strategies across subsequent semesters. Those students that did not change were generally high achievers, believing their study approaches were most effective, but their performance did not improve across semesters. In contrast, students who adapted, mostly by modifying how they appraised and rearranged records or improved planning and time management, performed less well overall but significantly improved their performance across semesters. Meta-learning tasks may prompt students to become more self-reflective and independent learners by affecting their approach to learning, enabling them to reflect on their study strategies, adapt and improve performance, and may enable the development of lifelong learning skills.

CLIPS (Communication Learning in Practice for Scientists): A New Online Resource Leverages Assessment to Help Students and Academics Improve Science Communication

The ability to communicate is a crucial graduate outcome for science students; however, crowded curricula and large class sizes make it difficult to find time to explicitly teach foundational communication skills. In response to these challenges, we developed an online resource called Communication Learning in Practice for Scientists, or CLIPS. CLIPS provides a multi-point mentoring model that has allowed us to successfully integrate the teaching and learning of a complex set of tacitly-understood skills across multiple scientific disciplines. It also provides a flexible way for industry experts, academics, and students to learn from one another’s experiences of, and expertise in, science communication. CLIPS leverages the student focus on assessment; students access CLIPS for pragmatic, detailed, and consistent advice when undertaking assessment tasks. In creating CLIPS, our philosophy was that communication is the core business of any scientific practice, not an add-on after the event. Extensive, repeated use of CLIPS by both students and academics indicates that the resource and its delivery model are considered useful, respected, and impactful for, and by, the intended audiences. We have provided CLIPS to the science education community through www.clips.edu.au.

Oral administration of green plant-derived chemicals and antioxidants alleviates stress-induced cellular oxidative challenge

Abstract Background: This study examined the efficacy of the combination antioxidant, Formula 42 (F42), on cellular stress indicators in animal and human models of stress-induced oxidative stress. Methods: A sub-chronic psychological stress model in rodents was used to induce stress and oxidative stress indicators over a 10-day period during which animals received oral doses of F42 or water. Following treatment, body weight, plasma stress hormone corticosterone, and oxidative capacity were evaluated. In healthy human subjects, a randomized double-blind crossover study was used to examine the antioxidant effect of F42 or placebo in an exercise-induced oxidative stress model. Erythrocyte and plasma oxidative status was evaluated using the fluorescent activation of 2′,7′-dichlorofluorescin (DCF) as an indicator. Results: Oral administration of F42 reduced the corticosterone response to acute stress compared to vehicle but did not differ at the conclusion of the 10-day study. However, F42 administration did reduce stress-induced growth restriction and alleviate DCF activation in circulating erythrocytes by approximately 10% following 10 days of stress exposure. Oral administration of F42 also significantly reduced DCF activation by approximately 10% in healthy human subjects undergoing exercise-induced oxidative stress. Conclusions: Oral administration of F42 in rodents produces transient reductions in stress hormones and reduces stress indicators following sub-chronic psychological stress exposure. In humans, F42 acts as an early and potent antioxidant capable of scavenging free radicals within 30 min of ingestion.