Experimental design and analysis and their reporting: new guidance for publication in BJP

Background and PurposeA non‐psychoactive phytocannabinoid, cannabidiol (CBD), shows promising results as an effective potential antiepileptic drug in some forms of refractory epilepsy. To elucidate the mechanisms by which CBD exerts its anti‐seizure effects, we investigated its effects at synaptic connections and on the intrinsic membrane properties of hippocampal CA1 pyramidal cells and two major inhibitory interneurons: fast spiking, parvalbumin (PV)‐expressing and adapting, cholecystokinin (CCK)‐expressing interneurons. We also investigated whether in vivo treatment with CBD altered the fate of CCK and PV interneurons using immunohistochemistry.Experimental ApproachElectrophysiological intracellular whole‐cell recordings combined with neuroanatomy were performed in acute brain slices of rat temporal lobe epilepsy in in vivo (induced by kainic acid) and in vitro (induced by Mg2+‐free solution) epileptic seizure models. For immunohistochemistry experiments, CBD was administered in vivo (100 mg·kg−1) at zero time and 90 min post status epilepticus, induced with kainic acid.Key ResultsBath application of CBD (10 μM) dampened excitability at unitary synapses between pyramidal cells but enhanced inhibitory synaptic potentials elicited by fast spiking and adapting interneurons at postsynaptic pyramidal cells. Furthermore, CBD restored impaired membrane excitability of PV, CCK and pyramidal cells in a cell type‐specific manner. These neuroprotective effects of CBD were corroborated by immunohistochemistry experiments that revealed a significant reduction in atrophy and death of PV‐ and CCK‐expressing interneurons after CBD treatment.Conclusions and ImplicationsOur data suggest that CBD restores excitability and morphological impairments in epileptic models to pre‐epilepsy control levels through multiple mechanisms to reinstate normal network function.

Section: Methodsmentioning

confidence: 99%

Cannabidiol exerts antiepileptic effects by restoring hippocampal interneuron functions in a temporal lobe epilepsy model

Khan

Shekh‐Ahmad²,

Khalil³

et al. 2018

“…The T‐maze continuous alternation was performed as described previously (Delotterie et al, 2015). This behavioural task is based on the natural propensity of the animal to explore new environments, referred as to as neophilia, or novelty preference.…”

Section: Methodsmentioning

confidence: 99%

Targeting the dopamine D₁ receptor or its downstream signalling by inhibiting phosphodiesterase‐1 improves cognitive performance

Pekcec

Schülert

Stierstorfer

et al. 2018

Background and PurposeInsufficient prefrontal dopamine 1 (D1) receptor signalling has been linked to cognitive dysfunction in several psychiatric conditions. Because the PDE1 isoform B (PDE1B) is postulated to regulate D1 receptor‐dependent signal transduction, in this study we aimed to elucidate the role of PDE1 in cognitive processes reliant on D1 receptor function.Experimental ApproachCognitive performance of the D1 receptor agonist, SKF38393, was studied in the T‐maze continuous alternation task and 5‐choice serial reaction time task. D1 receptor/PDE1B double‐immunohistochemistry was performed using human and rat prefrontal brain sections. The pharmacological activity of the PDE1 inhibitor, ITI‐214, was assessed by measuring the increase in cAMP/cGMP in prefrontal brain tissue and its effect on working memory performance. Mechanistic studies on the modulation of prefrontal neuronal transmission by SKF38393 and ITI‐214 were performed using extracellular recordings in brain slices.Key ResultsSKF38393 improved working memory and attentional performance in rodents. D1 receptor/PDE1B co‐expression was verified in both human and rat prefrontal brain sections. The pharmacological activity of ITI‐214 on its target, PDE1, was demonstrated by its ability to increase prefrontal cAMP/cGMP. In addition, ITI‐214 improved working memory performance. Both SKF38393 and ITI‐214 facilitated neuronal transmission in prefrontal brain slices.Conclusion and ImplicationsWe hypothesize that PDE1 inhibition improves working memory performance by increasing prefrontal synaptic transmission and/or postsynaptic D1 receptor signalling, by modulating prefrontal downstream second messenger levels. These data, therefore, support the use of PDE1 inhibitors as a potential approach for the treatment of cognitive dysfunction.

“…HL‐1 cardiomyocyte studies were performed using six to eight preparations for each endpoint, but data for a whole experiment were discarded if on occasion a response to DOX was not obtained. Data and statistical analysis comply with the recommendations on experimental design and analysis in pharmacology (Curtis et al, 2015). …”

Section: Methodsmentioning

confidence: 99%

Signalling mechanisms underlying doxorubicin and Nox2 NADPH oxidase‐induced cardiomyopathy: involvement of mitofusin‐2

McLaughlin

Zhao

O’Neill

et al. 2017

Background and PurposeThe anthracycline doxorubicin (DOX), although successful as a first‐line cancer treatment, induces cardiotoxicity linked with increased production of myocardial ROS, with Nox2 NADPH oxidase‐derived superoxide reported to play a key role. The aim of this study was to identify novel mechanisms underlying development of cardiac remodelling/dysfunction further to DOX‐stimulated Nox2 activation.Experimental ApproachNox2−/− and wild‐type (WT) littermate mice were administered DOX (12 mg·kg−1 over 3 weeks) prior to study at 4 weeks. Detailed mechanisms were investigated in murine HL‐1 cardiomyocytes, employing a robust model of oxidative stress, gene silencing and pharmacological tools.Key ResultsDOX‐induced cardiac dysfunction, cardiomyocyte remodelling, superoxide production and apoptosis in WT mice were attenuated in Nox2−/− mice. Transcriptional analysis of left ventricular tissue identified 152 differentially regulated genes (using adjusted P < 0.1) in DOX‐treated Nox2−/− versus WT mice, and network analysis highlighted ‘Cell death and survival’ as the biological function most significant to the dataset. The mitochondrial membrane protein, mitofusin‐2 (Mfn2), appeared as a strong candidate, with increased expression (1.5‐fold), confirmed by qPCR (1.3‐fold), matching clear published evidence of promotion of cardiomyocyte cell death. In HL‐1 cardiomyocytes, targeted siRNA knockdown of Nox2 decreased Mfn2 protein expression, but not vice versa. While inhibition of Nox2 activity along with DOX treatment attenuated its apoptotic and cytotoxic effects, reduced apoptosis after Mfn2 silencing reflected a sustained cytotoxic response and reduced cell viability.Conclusions and ImplicationsDOX‐induced and Nox2‐mediated up‐regulation of Mfn2, rather than contributing to cardiomyocyte dysfunction through apoptotic pathways, appears to promote a protective mechanism.Linked ArticlesThis article is part of a themed section on New Insights into Cardiotoxicity Caused by Chemotherapeutic Agents. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.21/issuetoc