ABSTRACT
Dipyrone (Dp), 4-aminoantipyrine (AA), and antipyrine (At) delay liquid gastric emptying (GE) in rats. We evaluated adrenergic participation in this phenomenon in a study in male Wistar rats (250-300 g) pretreated subcutaneously with guanethidine (GUA), 100 mg·kg−1·day−1, or vehicle (V) for 2 days before experimental treatments. Other groups of animals were pretreated intravenously (iv) 15 min before treatment with V, prazosin (PRA; 1 mg/kg), yohimbine (YOH; 3 mg/kg), or propranolol (PRO; 4 mg/kg), or with intracerebroventricular (icv) administration of 25 µg PRO or V. The groups were treated iv with saline or with 240 µmol/kg Dp, AA, or At. GE was determined 10 min later by measuring the percentage of gastric retention (%GR) of saline labeled with phenol red 10 min after gavage. %GR (mean±SE, n=8) indicated that GUA abolished the effect of Dp (GUA vs V=31.7±1.6 vs 47.1±2.3%) and of At (33.2±2.3 vs 54.7±3.6%) on GE and significantly reduced the effect of AA (48.1±3.2 vs 67.2±3.1%). PRA and YOH did not modify the effect of the drugs. %GR (mean±SE, n=8) indicated that iv, but not icv, PRO abolished the effect of Dp (PRO vs V=29.1±1.7 vs 46.9±2.7%) and At (30.5±1.7 vs 49±3.2%) and significantly reduced the effect of AA (48.4±2.6 vs 59.5±3.1%). These data suggest activation of peripheral β-adrenoceptors in the delayed GE induced by phenylpyrazolone derivatives.
Subject(s)
Animals , Male , Adrenergic Antagonists/administration & dosage , Ampyrone/administration & dosage , Anti-Inflammatory Agents, Non-Steroidal/administration & dosage , Antipyrine/administration & dosage , Dipyrone/administration & dosage , Gastric Emptying/drug effects , Receptors, Adrenergic, beta/metabolism , Infusions, Intraventricular , Phenolsulfonphthalein , Prazosin/administration & dosage , Propranolol/administration & dosage , Rats, Wistar , Yohimbine/administration & dosageABSTRACT
Glaucoma is a neurodegenerative disease characterized by loss of retinal ganglion cells and their axons. Recent evidence suggests that intraocular pressure (IOP) is only one of the many risk factors for this disease. Current treatment options for this disease have been limited to the reduction of IOP; however, it is clear now that the disease progression continues in many patients despite effective lowering of IOP. In the search for newer modalities in treating this disease, much data have emerged from experimental research the world over, suggesting various pathological processes involved in this disease and newer possible strategies to treat it. This review article looks into the current understanding of the pathophysiology of glaucoma, the importance of neuroprotection, the various possible pharmacological approaches for neuroprotection and evidence of current available medications.
Subject(s)
Administration, Topical , Adrenergic Antagonists/administration & dosage , Antihypertensive Agents/administration & dosage , Carbonic Anhydrase Inhibitors/administration & dosage , Clinical Trials as Topic , Evidence-Based Medicine/methods , Glaucoma/drug therapy , Glaucoma/physiopathology , Humans , Neuroprotective Agents/therapeutic use , Prostaglandins/administration & dosageABSTRACT
Los Betabloqueantes son drogas que inhiben competitivamente a los receptores beta-adrenérgicos, modulando la actividad de el sistema nervioso simpático. Estos son normalmente clasificados en base a su selectividad por los receptores beta. Los beta bloqueantes no selectivos, como propanolol, pindolol, nadolol, timolol y labetalol antagonizan los receptores B1 y B2. Los beta-bloqueantes selectivos, como el metoprolol, atenolol, esmolol y acebutolol tienen mayor afinidad por los receptores B-1. Los beta-bloqueantes selectivos están indicados en pacientes en quienes el bloqueo B-2 puede asociar un aumento en el riesgo de efectos adversos. Como en pacientes asmáticos o diabéticos, así como en pacientes con enfermedad vascular periférica o enfermedad de Raynaud. Algunos betabloqueantes tienen actividad agonista parcial (actividad simpático mimétrica intrínseca). Los beta-bloqueantes, como monoterapia o combinados con otras drogas han probado que tienen efectividad en la reducción de síntomas de angina de pecho y reducción de la morbi-mortalidad después del infarto al miocardio. Además son las drogas de elección en pacientes con hipertensión arterial e infarto al miocardio o angina. Muchos beta-bloqueantes son comúnmente usados en el tratamiento de pacientes con migraña recurrente, cardiomiopatía hipertrófica obstructiva, ansiedad aguda y en casos de glaucoma. En este artículo se presenta una revisión detallada sobre los beta-bloqueantes en el tratamiento de la hipertension arterial