Protective Effect of Mormodica balsamina Leaf Extract on the Gastric Morphology of Experimental Rats Against Ethanol Induced Gastric Ulcers / Efecto Protector de los Extractos de Hojas de Mormodica balsamina en la Morfología Gástrica de Ratas Experimentales Contra Úlceras Gástricas Inducidas por Etanol

SUMMARY: Mormodica balsamina is a valuable medicinal plant that is used to treat wounds and inflammation; its leaves are also used as an antibiotic and in the treatment of stomach pain. This study was conducted to determine the anti-ulcer activity of methanolic leaf extract of Mormodica balsamina on ethanol-induced ulcer in albino rats. A total of 32 rats were used for the study. Groups I and II served as the baseline and negative controls respectively, while groups III-VII served as the test groups. Group I was untreated, while group II received 1ml/kg body weight of the vehicle (2 % DMSO). Three test groups (III - V) received methanol extracts (75 mg, 150 mg, 300 mg/kg body weight respectively) while the other three test groups (VI - VIII) received aqueous extracts (75 mg, 150mg, 300 mg/kg body weight respectively) via oral gavage for seven days prior to ulcer induction. The rats were sacrificed, stomachs excised and ulcers scored. Histological sections were produced and examined. Findings revealed that M. balsamina extracts protected the rats' gastric epithelia from ethanol induced ulceration to varying degree with the high dose (150 and 300 mg/kg) of both extracts offering the best preservation (42 % and 50 % ulcer protective index respectively) when compared to untreated animals. Histological findings correlated with calculated ulcer indices, with treated animals having less severe gastric mucosal lesions. In conclusion, extracts of M. balsamina may possess reasonable antiulcer activities in rats against ethanol induced gastric ulcer.

Mormodica balsamina es una valiosa planta medicinal que se utiliza para tratar heridas e inflamaciones; sus hojas también se utilizan como antibiótico y en el tratamiento del dolor de estómago. Este estudio se realizó para determinar la actividad antiulcerosa del extracto metanólico de hojas de Mormodica balsamina sobre la úlcera inducida por etanol en ratas albinas. Se utilizaron un total de 32 ratas para el estudio. Los grupos I y II sirvieron como referencia y controles negativos respectivamente, mientras que los grupos III-VII sirvieron como grupos de prueba. El grupo I no se trató, mientras que el grupo II recibió 1 ml/kg de peso corporal del vehículo (2% de DMSO). Tres grupos de prueba (III - V) recibieron extractos de metanol (75 mg, 150 mg, 300 mg/ kg de peso corporal respectivamente) mientras que los otros tres grupos de prueba (VI - VIII) recibieron extractos acuosos (75 mg, 150 mg, 300 mg/kg de peso corporal respectivamente) por sonda oral durante siete días antes de la inducción de la úlcera. Se sacrificaron las ratas, se extirparon los estómagos y se puntuaron las úlceras. Se realizaron y examinaron secciones histológicas. Los resultados revelaron que los extractos de M. balsamina protegieron el epitelio gástrico de las ratas de la ulceración inducida por etanol en diversos grados, y la dosis alta (150 y 300 mg/kg) de ambos extractos ofreció la mejor conservación (42 % y 50 % de índice de protección contra úlceras, respectivamente) en comparación con los animales no tratados. Los hallazgos histológicos se correlacionaron con los índices de úlcera calculados, y los animales tratados tenían lesiones de la mucosa gástrica menos graves. En extractos de M. balsamina puede poseer actividades antiulcerosas razonables en ratas contra la úlcera gástrica inducida por etanol.

Arc 3' UTR Splicing Leads to Dual and Antagonistic Effects in Fine-Tuning Arc Expression Upon BDNF Signaling.

Activity-regulated cytoskeletal associated protein (Arc) is an immediate-early gene critically involved in synaptic plasticity and memory consolidation. Arc mRNA is rapidly induced by synaptic activation and a portion is locally translated in dendrites where it modulates synaptic strength. Being an activity-dependent effector of homeostatic balance, regulation of Arc is uniquely tuned to result in short-lived bursts of expression. Cis-Acting elements that control its transitory expression post-transcriptionally reside primarily in Arc mRNA 3' UTR. These include two conserved introns which distinctively modulate Arc mRNA stability by targeting it for destruction via the nonsense mediated decay pathway. Here, we further investigated how splicing of the Arc mRNA 3' UTR region contributes to modulate Arc expression in cultured neurons. Unexpectedly, upon induction with brain derived neurotrophic factor, translational efficiency of a luciferase reporter construct harboring Arc 3' UTR is significantly upregulated and this effect is dependent on splicing of Arc introns. We find that, eIF2α dephosphorylation, mTOR, ERK, PKC, and PKA activity are key to this process. Additionally, CREB-dependent transcription is required to couple Arc 3' UTR-splicing to its translational upregulation, suggesting the involvement of de novo transcribed trans-acting factors. Overall, splicing of Arc 3' UTR exerts a dual and unique effect in fine-tuning Arc expression upon synaptic signaling: while inducing mRNA decay to limit the time window of Arc expression, it also elicits translation of the decaying mRNA. This antagonistic effect likely contributes to the achievement of a confined yet efficient burst of Arc protein expression, facilitating its role as an effector of synapse-specific plasticity.

Kek-6: A truncated-Trk-like receptor for Drosophila neurotrophin 2 regulates structural synaptic plasticity.

Neurotrophism, structural plasticity, learning and long-term memory in mammals critically depend on neurotrophins binding Trk receptors to activate tyrosine kinase (TyrK) signaling, but Drosophila lacks full-length Trks, raising the question of how these processes occur in the fly. Paradoxically, truncated Trk isoforms lacking the TyrK predominate in the adult human brain, but whether they have neuronal functions independently of full-length Trks is unknown. Drosophila has TyrK-less Trk-family receptors, encoded by the kekkon (kek) genes, suggesting that evolutionarily conserved functions for this receptor class may exist. Here, we asked whether Keks function together with Drosophila neurotrophins (DNTs) at the larval glutamatergic neuromuscular junction (NMJ). We tested the eleven LRR and Ig-containing (LIG) proteins encoded in the Drosophila genome for expression in the central nervous system (CNS) and potential interaction with DNTs. Kek-6 is expressed in the CNS, interacts genetically with DNTs and can bind DNT2 in signaling assays and co-immunoprecipitations. Ligand binding is promiscuous, as Kek-6 can also bind DNT1, and Kek-2 and Kek-5 can also bind DNT2. In vivo, Kek-6 is found presynaptically in motoneurons, and DNT2 is produced by the muscle to function as a retrograde factor at the NMJ. Kek-6 and DNT2 regulate NMJ growth and synaptic structure. Evidence indicates that Kek-6 does not antagonise the alternative DNT2 receptor Toll-6. Instead, Kek-6 and Toll-6 interact physically, and together regulate structural synaptic plasticity and homeostasis. Using pull-down assays, we identified and validated CaMKII and VAP33A as intracellular partners of Kek-6, and show that they regulate NMJ growth and active zone formation downstream of DNT2 and Kek-6. The synaptic functions of Kek-6 could be evolutionarily conserved. This raises the intriguing possibility that a novel mechanism of structural synaptic plasticity involving truncated Trk-family receptors independently of TyrK signaling may also operate in the human brain.