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Aims: Phosphodiesterase 2 (PDE2) regulates intracellular cyclic adenosine monophosphate and guanosine monophosphate (cAMP/cGMP) levels, which contribute to processes crucial for learning and memory. BI 474121, a potent and selective PDE2 inhibitor, is in development for treating cognitive impairment associated with schizophrenia. Methods: The effects of BI 474121 on cGMP concentrations were first assessed in rat cerebrospinal fluid (CSF) to demonstrate central nervous system (CNS) and functional target engagement. Next, a Phase I study in healthy participants assessed the pharmacokinetics of BI 474121 in CSF vs. plasma, the pharmacodynamics of BI 474121 by measuring cGMP concentrations in the CSF, and the safety of BI 474121. Results: In rats, BI 474121 was associated with a dose‐dependent increase (71% at the highest dose tested [3.0 mg kg−1]) in cGMP levels in the CSF relative to vehicle (P < 0.001). In healthy participants, the maximum‐measured concentration CSF‐to‐plasma ratio for BI 474121 exposure was similar following single oral doses of BI 474121 2.5, 10, 20 and 40 mg (dose‐adjusted geometric mean: 8.96% overall). BI 474121 2.5–40 mg administration in healthy participants also increased cGMP levels in CSF (maximum exposure‐related change from baseline ratio, BI 474121: 1.44–2.20 vs. placebo: 1.26). The most common treatment‐emergent adverse event (AE) was mild‐to‐moderate post‐lumbar puncture syndrome, which resolved with standard treatment. No AEs of special interest were observed. Conclusions: BI 474121 crosses the blood–brain barrier to inhibit PDE2, supporting cGMP as a translational marker to monitor CNS target engagement. These findings promote further clinical development of BI 474121. ClinicalTrials.gov number (NCT04672954). [ABSTRACT FROM AUTHOR]

Background: Noradrenergic signaling declines in Parkinson's disease (PD) following locus coeruleus neurodegeneration. Epidemiologic studies demonstrate that β-acting drugs slow PD progression. Objective: The primary objective was to compare the safety and effects of 3 β-adrenoceptor (β-AR) acting drugs on central nervous system (CNS) function after a single dose in healthy volunteers (HVs) and evaluate the effects of multiple doses of β-AR acting drugs in HVs and PD-patients. Methods: In Part A, HVs received single doses of 32 mg salbutamol, 160μg clenbuterol, 60 mg pindolol and placebo administered in a randomized, 4-way cross-over study. In Part B (randomized cross-over) and Part C (parallel, 2:1 randomized), placebo and/or clenbuterol (20μg on Day 1, 40μg on Day 2, 80μg on Days 3–7) were administered. CNS functions were assessed using the NeuroCart test battery, including pupillometry, adaptive tracking and recall tests. Results: Twenty-seven HVs and 12 PD-patients completed the study. Clenbuterol improved and pindolol reduced the adaptive tracking and immediate verbal recall performance. Clenbuterol and salbutamol increased and pindolol decreased pupil-to-iris ratios. Clenbuterol was selected for Parts B and C. In Part B, clenbuterol significantly increased performance in adaptive tracking with a tendency toward improved performance in immediate and delayed verbal recall. In Part C trends toward improved performance in immediate and delayed verbal recall were observed in PD-patients. Typical cardiovascular peripheral β2-AR effects were observed with clenbuterol. Conclusions: This study demonstrates the pro-cognitive effects of clenbuterol in HVs with similar trends in PD-patients. The mechanism of action is likely activation of β2-ARs in the CNS. Plain Language Summary: Aims and Purpose of the Research: This research aimed to explore how three different drugs affect brain function. These drugs are salbutamol, clenbuterol, and pindolol and work in the brain by stimulating specific brain cells that can improve aspects like memory and coordination. The main question was to see how safe these drugs were and how they impact the brain function after one dose in healthy people, and after multiple doses in both healthy people and those with Parkinson's disease. Background of the Research: Parkinson's disease is a condition where brain cells start to die, which affects different areas of the brain, including movement function, as well as memory and attention. This research matters because finding drugs that affect the brain function could improve the lives of people with Parkinson's disease. Methods and Research Design: The study was conducted in three parts. In the first part, healthy volunteers took one dose of each of the three drugs— salbutamol, clenbuterol, and pindolol— as well as a placebo (a harmless pill that has no effect). The researchers tested the participants' brain functions using various tasks including memory tests and eye response measurements. In the second and third part, healthy people and people with Parkinson's disease took the drug that performed best in healthy volunteers for seven days. Results and Importance: In the first part, a single dose of clenbuterol was safe and improved memory and attentions tasks in healthy people, and therefore was chosen for further testing in the second and third part. In these parts, multiple doses of clenbuterol were safe and helped improve memory and attention tasks in healthy people, with similar positive trends seen in people with Parkinson's disease. The study suggests that clenbuterol might help improve brain function by activating specific receptors in the brain. These results are important because they suggest that clenbuterol could be a potential treatment to help improve brain function in people with Parkinson's disease. However, more research is needed to fully understand its effects and to confirm these findings. [ABSTRACT FROM AUTHOR]

Compared detailed (favoring field dependence and induction) and nondetailed (favoring field dependence and deduction) assignments on biology achievement of grade 10 male students (N=95) over a seven-month period. Detailed assignments, employing pictorial and verbal block diagrams and high structure, significantly enhanced learning among some students. (JN)