Pedro Valada

Mr. Pedro Valada

University of Coimbra
orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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Journal Article
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PVPedro Valada
Pedro Valada
SASofia Alçada-Morais
Sofia Alçada-Morais
Rodrigo CunhaRodrigo Cunha
Rodrigo Cunha
JLJoão Pedro Lopes
João Pedro Lopes
Theobromine is a caffeine metabolite most abundant in dark chocolate, of which consumption is linked with a lower risk of cognitive decline. However, the mechanisms through which theobromine affects neuronal function remain ill-defined. Using electrophysiological recordings in mouse hippocampal synapses, we now characterized the impact of a realistic concentration of theobromine on synaptic transmission and plasticity. Theobromine (30 μM) facilitated synaptic transmission while decreasing the magnitude of long-term potentiation (LTP), with both effects being blunted by adenosine deaminase (2 U/mL). The pharmacological blockade of A1R with DPCPX (100 nM) eliminated the theobromine-dependent facilitation of synaptic transmission, whereas the A2AR antagonist SCH58261 (50 nM), as well as the genetic deletion of A2AR, abrogated the theobromine-induced impairment of LTP. Furthermore, theobromine prevented LTP deficits and neuronal loss, respectively, in mouse hippocampal slices and neuronal cultures exposed to Aβ1–42 peptides, considered a culprit of Alzheimer’s disease. Overall, these results indicate that theobromine affects information flow via the antagonism of adenosine receptors, normalizing synaptic plasticity and affording neuroprotection in dementia-related conditions in a manner similar to caffeine.

Verified
Journal Article
Open access
PDF file
PVPedro Valada
Pedro Valada
AMAna Mata
Ana Mata
RBRui Brito
Rui Brito
Teresa GonçalvesTeresa Gonçalves
Teresa Gonçalves
JMJose Augusto, Silva Medeiros
Jose Augusto, Silva Medeiros
CNCélia Nogueira
Célia Nogueira
Antibiotic resistance in Helicobacter pylori is increasing rapidly and emerging as a major factor in treatment failure. We aimed to identify genetic mutations associated with resistance to clarithromycin (23S rRNA peptidyl transferase), fluoroquinolones (gyrA), and metronidazole (rdxA), and to explore their mechanisms of action through molecular modeling. H. pylori detection and the molecular characterization of genes were conducted directly on gastric biopsies by real-time PCR followed by nucleotide sequencing. A 3D model was used to evaluate molecular interactions between the antibiotics and respective target proteins. H. pylori was identified in 66.7% of 33 patients. An analysis of 23SrRNA revealed novel mutations that, by in silico analysis, do not appear to contribute to clarithromycin resistance. In gyrA, mutations in amino acid residues 87 and 91 had an incidence of 27%, and the in silico analysis revealed that these positions are relevant in the binding and resistance to fluoroquinolones. It is also reported for other mutations, some of which are never described. All rdxA mutations were missense, with R16H, M56V, H97T, G98S, A118T, V123T, and R131K predicted by in silico analysis to impact metronidazole resistance. Monitoring H. pylori gene mutations is crucial for tailoring effective antibiotic therapies. Our study advances personalized medicine by introducing novel methods to detect resistance-related mutations and uncovering the molecular mechanisms driving this resistance.