RESUMO
BACKGROUND: Oral and intravenous gabapentin can markedly attenuate blood pressure (BP) in hypertensive rats. The nucleus tractus solitarii (NTS) is the primary integrative center for cardiovascular control and other autonomic functions in the central nervous system. However, the signaling mechanisms involved in gabapentin-mediated cardiovascular effects in the NTS remain unclear. We investigated whether the nitric oxide synthase (NOS) signaling pathway was involved in gabapentin-mediated BP regulation in the NTS of spontaneously hypertensive (SHR) rats. METHODS: SHR rats were anesthetized with urethane at age 10-12 weeks. Arterial pressure and heart rate (HR) were monitored through a femoral artery catheter. For stereotaxic intra-NTS microinjection, the dorsal surface of the medulla was exposed by limited craniotomy. We observed that unilateral microinjection of gabapentin into the NTS whether to change dose-related BP and HR. Then, unilateral microinjection of gabapentin into the NTS before and after N(ω)-nitro-L-arginine methyl ester (L-NAME) treatment whether to change blood pressure and heart rate. RESULTS: Unilateral microinjection of gabapentin into the NTS produced prominent dose-related depressor and bradycardic effects in SHR rats. The cardiovascular effects of gabapentin were attenuated by the prior administration of the NOS inhibitor, L-NAME. CONCLUSIONS: Gabapentin modulated central BP and HR control in the NTS of SHR rats in this study through NOS signaling.
RESUMO
The effect of the anti-inflammatory compound NPC-14686 on intracellular Ca²âº concentration ([Ca²âº](i)) and viability in OC2 human oral cancer cells was investigated. The Ca²âº-sensitive fluorescent probe fura-2 was used to examine [Ca²âº](i). NPC-14686 induced [Ca²âº](i) rises in a concentration-dependent fashion. The effect was reduced approximately by 10% by removing extracellular Ca²âº. NPC-14686- elicited Ca²âº signal was decreased by nifedipine, econazole, SKF96365, and GF109203X. In Ca²âº-free medium, incubation with the endoplasmic reticulum Ca²âº pump inhibitor thapsigargin or 2,5-di-tert-butylhydroquinone (BHQ) abolished NPC-14686-induced [Ca²âº](i) rises. Conversely, pretreatment with NPC-14686 abolished thapsigargin or BHQ-induced [Ca²âº](i) rises. Inhibition of phospholipase C with U73122 abolished NPC-14686-induced [Ca²âº](i) rises. At 20-100 µM, NPC-14686 inhibited cell viability, which was not reversed by chelating cytosolic Ca²âº with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'- tetraacetic acid-acetoxymethyl ester (BAPTA/AM). NPC-14686 between 20 µM and 40 µM also induced apoptosis. Collectively, in OC2 cells, NPC-14686 induced [Ca²âº](i) rises by evoking phospholipase C-dependent Ca²âº release from the endoplasmic reticulum and Ca²âº entry via protein kinase C-regulated store-operated Ca²âº channels. NPC-14686 also caused Ca²âº-independent apoptosis.
Assuntos
Aminobutiratos/uso terapêutico , Apoptose/efeitos dos fármacos , Cálcio/metabolismo , Carcinoma de Células Escamosas/tratamento farmacológico , Neoplasias Bucais/tratamento farmacológico , Aminobutiratos/farmacologia , Canais de Cálcio/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Retículo Endoplasmático/metabolismo , Fura-2 , Homeostase , Humanos , Fosfolipases Tipo C/metabolismoRESUMO
Safrole is a carcinogen found in plants. The effect of safrole on cytosolic free Ca²âº concentrations ([Ca²âº](i)) and viability in SCM1 human gastric cancer cells was explored. The Ca²âº-sensitive fluorescent dye fura-2 was applied to measure [Ca²âº](i). Safrole at concentrations of 150-450 µM induced a [Ca²âº](i) rise in a concentration-dependent manner. The response was reduced by 60% by removing extracellular Ca²âº. Safrole-evoked Ca²âº entry was not altered by nifedipine, econazole, SKF96365, and protein kinase C activator or inhibitor. In Ca²âº-free medium, treatment with the endoplasmic reticulum Ca²âº pump inhibitor thapsigargin or 2,5-di-tert-butylhydroquinone (BHQ) abolished safrole-evoked [Ca²âº](i) rises. Conversely, treatment with safrole abolished thapsigargin or BHQ-evoked [Ca²âº](i) rises. Inhibition of phospholipase C (PLC) with U73122 abolished safrole-induced [Ca²âº](i) rises. At 250-550 µM, safrole decreased cell viability concentration-dependently, which was not reversed by chelating cytosolic Ca²âº with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/acetoxy methyl (BAPTA/AM). Annexin V/propidium iodide staining data suggest that safrole (350-550 µM) induced apoptosis concentration-dependently. These studies suggest that in SCM1 human gastric cancer cells, safrole induced [Ca²âº](i) rises by inducing PLC-dependent Ca²âº release from the endoplasmic reticulum and Ca²âº influx via non-store-operated Ca²âº entry pathways. Safrole-induced cell death may involve apoptosis.
