L'apotecari català Josep Antoni Savall i la seva reivindicació d'una nova farmacopea a la ciutat de Barcelona i principat de Catalunya l'any 1788

En aquesta comunicació es dóna a conèixer la tasca realitzada per l’apotecari Josep Antoni Savall, considerat figura rellevant en la transició de l’apotecari al farmacèutic, així com la seva reivindicació d’una farmacopea nova a la ciutat de Barcelona i principat de Catalunya a l’any 1788 després de més de cent anys de  l’edició de la Farmacopea Catalana de Joan d’Alós (1686) i de dos-cents de la última edició de la “Concordia Apothecariorum Bardrinonensium “(1587).En esta comunicación se da a conocer la labor realizada por el boticario Joan Antoni Savall, considerado figura relevante en la transición del boticario al farmacéutico, así como su reivindicación de una nueva farmacopea en la  Ciudad de Barcelona y Principado de Catalunya en el año 1788, después de más de cien años de la Farmacopea Catalana de Juan de Alós (1686) y  doscientos de la última edición de la “Concordia Apothecariorum Bardrinonensium” (1587)

Key structural determinants in the agonist binding loops of human β2 and β4 nicotinic acetylcholine receptor subunits contribute to α3β4 subtype selectivity of α-conotoxins

α-Conotoxins represent a large group of pharmacologically active peptides that antagonize nicotinic acetylcholine receptors (nAChRs). The α3β4 nAChR, a predominant subtype in the peripheral nervous system, has been implicated in various pathophysiological conditions. As many α-conotoxins have multiple pharmacological targets, compounds specifically targeting individual nAChR subtypes are needed. In this study, we performed mutational analyses to evaluate the key structural components of human β2 and β4 nAChR subunits that determine α-conotoxin selectivity for α3β4 nAChR. α-Conotoxin RegIIA was used to evaluate the impact of non-conserved human β2 and β4 residues on peptide affinity. Two mutations, α3β2[T59K] and α3β2[S113R], strongly enhanced RegIIA affinity compared with wild-type α3β2, as seen by substantially increased inhibitory potency and slower off-rate kinetics. Opposite point mutations in α3β4 had the contrary effect, emphasizing the importance of loop D residue 59 and loop E residue 113 as determinants for RegIIA affinity. Molecular dynamics simulation revealed the side chains of β4 Lys59 and β4 Arg113 formed hydrogen bonds with RegIIA loop 2 atoms, whereas the β2 Thr59 and β2 Ser113 side chains were not long enough to form such interactions. Residue β4 Arg113 has been identified for the first time as a crucial component facilitating antagonist binding. Another α-conotoxin, AuIB, exhibited low activity at human α3β2 and α3β4 nAChRs. Molecular dynamics simulation indicated the key interactions with the β subunit are different to RegIIA. Taken together, these data elucidate the interactions with specific individual β subunit residues that critically determine affinity and pharmacological activity of α-conotoxins RegIIA and AuIB at human nAChRs

Alanine scan ofα-conotoxin regIIA reveals a selective α3β4 nicotinic acetylcholine receptor antagonist

Activation of the alpha 3 beta 4 nicotinic acetylcholine receptor (nAChR) subtype has recently been implicated in the pathophysiology of various conditions, including development and progression of lung cancer and in nicotine addiction. As selective alpha 3 beta 4 nAChR antagonists, alpha-conotoxins are valuable tools to evaluate the functional roles of this receptor subtype. We previously reported the discovery of a new beta 4/7-conotoxin, RegIIA. RegIIA was isolated from Conus regius and inhibits acetylcholine (ACh)-evoked currents mediated by alpha 3 beta 4, alpha 3 beta 2, and alpha 7 nAChR subtypes. The current study used alanine scanning mutagenesis to understand the selectivity profile of RegIIA at the alpha 3 beta 4 nAChR subtype. [N11A] and [N12A] RegIIA analogs exhibited 3-fold more selectivity for the alpha 3 beta 4 than the alpha 3 beta 2 nAChR subtype. We also report synthesis of [N11A, N12A] RegIIA, a selective alpha 3 beta 4 nAChR antagonist (IC50 of 370 nM) that could potentially be used in the treatment of lung cancer and nicotine addiction. Molecular dynamics simulations of RegIIA and [N11A, N12A] RegIIA bound to alpha 3 beta 4 and alpha 3 beta 2 suggest that destabilization of toxin contacts with residues at the principal and complementary faces of alpha 3 beta 2 (alpha 3-Tyr(92), Ser(149), Tyr(189), Cys(192), and Tyr(196); beta 2-Trp(57), Arg(81), and Phe(119)) may form the molecular basis for the selectivity shift

Determinação de perdas de solo, água e nutrientes em Latossolo Amarelo, textura argilosa do Nordeste paraense.

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α-Conotoxins targeting neuronal nAChRs: understanding molecular pharmacology and potential therapeutics.

α-Conotoxins, a new class of peptides that act as nicotinic acetylcholine receptor (nAChR) antagonists have been identified from the venom of predatory marine cone snails. α-Conotoxins specifically target various nAChRs subtypes and are excellent molecular probes for identifying the physiological role of nAChR subtypes in both normal and disease states. nAChRs are ligand-gated ion channels expressed in both central nervous system (CNS) and peripheral nervous system (PNS) and are shown to contribute to the physiological roles of neurotransmitter release and synaptic plasticity. Further, they are also implicated in various conditions including Alzheimer’s disease and schizophrenia. The α3β4 subtype is shown to be involved in lung cancer and nicotine addiction. Despite this, the knowledge of the pathophysiological role of α3β4 subtypes is limited by the lack of adequate subtype specific probes. I report the discovery of new α4/7-conotoxin RegIIA which was isolated from Conus regius. Using alanine scanning mutagenesis, I report the synthesis of [N11A,N12A]RegIIA, a selective α3β4 nAChR antagonist (IC50 of 370 nM) that could potentially be used in the treatment of lung cancer and nicotine addiction. In this study, I also identified critical residues of α-conotoxin RegIIA that interact with the acetylcholine-binding site of α3β2, α3β4 and α7 nAChRs. My research also describes the pharmacological properties of two novel conotoxins: LsIA and GeXXA. α-Conotoxin LsIA is the first peptide isolated from Conus limpusi, a species of worm-hunting cone snail. LsIA exhibited selective and potent α7 and α3β2 nAChR subtype antagonism. These subtypes play vital roles in various functions, such as neuronal plasticity and synaptic transmission. In this report, I examined the structure–function relationship of a unique N-terminal serine and C-terminal carboxylation of LsIA. Furthermore, I also investigated the effect of α5 subunit incorporation, towards the inhibition of α3β2 nAChR subtype by LsIA. GeXXA is a novel αD-conotoxin isolated from the venom of Conus generalis. This toxin is a disulfide-linked homodimer of a 10-cysteine-containing peptide with each peptide chain made of 50 amino acid residues. αD-GeXXA is a non-selective inhibitor of muscle and neuronal nAChRs. Here I describe the functional characterization of monomeric αD–conotoxin which shows selective and reversible inhibition of α9α10 nAChR subtype. These results provide insight into the novel blocking mechanism of α-D conotoxins. α-Conotoxins inhibiting nAChRs have potential therapeutic applications. However, peptidic nature of α-conotoxins affects their stability and bioavailability. Various strategies to improve α-conotoxin stability have been implemented. Here, I explore the functional implications of dicarba modified cysteine bridges on novel analgesic α-conotoxins Vc1.1 and RgIA, which inhibit HVA calcium channel currents via GABAB receptor activation and α9α10 nAChR subtypes. My results revealed disulphide stacking interaction between the Cys2–Cys8 bond and disulphide of the C-loop of the principal subunit of nAChRs. My research describes the discovery, characterization and development of a novel α3β4 antagonist as neurophysiological and potential therapeutic tool for lung cancer. Further, dicarba modification of α-conotoxins and characterization of new class of α- and αD-conotoxins provide future insights towards drug development

Characterization of a novel alpha-conotoxin TxID from Conus textile that potently blocks rat alpha3/beta4 nicotinic acetylcholine receptors

The alpha 3 beta 4 nAChRs are implicated in pain sensation in the PNS and addiction to nicotine in the CNS. We identified an alpha-4/6-conotoxin (CTx) TxID from Conus textile. The new toxin consists of 15 amino acid residues with two disulfide bonds. TxID was synthesized using solid phase methods, and the synthetic peptide was functionally tested on nAChRs heterologously expressed in Xenopus laevis oocytes. TxID blocked rat alpha 3 beta 4 nAChRs with a 12.5 nM IC50, which places it among the most potent alpha 3 beta 4 nAChR antagonists. TxID also blocked the closely related alpha 6/alpha 3 beta 4 with a 94 nM IC50 but showed little activity on other nAChR subtypes. NMR analysis showed that two major structural isomers exist in solution, one of which adopts a regular alpha-CTx fold but with different surface charge distribution to other 4/6 family members. alpha-CTx TxID is a novel tool with which to probe the structure and function of alpha 3 beta 4 nAChRs