Acetylcholine-like activity in the fruit of the black nightshade (Solanaceae)

The presence of acetylcholine in aqueous extracts of the fruit of Solanum nigrum Linn. (black nightshade) has been established based upon the following pharmacological tests: a) isotonic contraction of the isolated toad rectus abdominis; b) negative chronotropic and inotropic action on the isolated toad heart; c) isotonic contraction of the isolated guinea pig’s ileum; d) isotonic contraction of the rat’s isolated jejunum; 3) decrease on the cat’s arterial blood pressure; f) secretory effects on the rat’s submaxillary gland. These actions were selectively blocked by curate or atropine and disappeared after incubation of the extract at 37 C with plasma. Further evidence showing that the fruit of the black nightshade contains acetylcholine was obtained by chromatographic separation of the aqueous extract. The average content of acetylcholine was found to be 250 micrograms/g of fruit.

Acetylcholine-like activity in the fruit of the black nightshade (Solanaceae).

The presence of acetylcholine in aqueous extracts of the fruit of Solanum nigrum Linn. (black nightshade) has been established based upon the following pharmacological tests: a) isotonic contraction of the isolated toad rectus abdominis; b) negative chronotropic and inotropic action on the isolated toad heart; c) isotonic contraction of the isolated guinea pigs ileum; d) isotonic contraction of the rats isolated jejunum; 3) decrease on the cats arterial blood pressure; f) secretory effects on the rats submaxillary gland. These actions were selectively blocked by curate or atropine and disappeared after incubation of the extract at 37 C with plasma. Further evidence showing that the fruit of the black nightshade contains acetylcholine was obtained by chromatographic separation of the aqueous extract. The average content of acetylcholine was found to be 250 micrograms/g of fruit.

Métodos no invasivos para evaluación del bloqueo beta-adrenergico / Non invasive methods for evaluation of beta adrenergic blockade

Con el objetivo de evaluar el grado de bloqueo ß-adrenérgico en 22 pacientes con cardiopatía isquémica, se estudiaron las respuestas cardíacas cronotrópica e inotrópica por medio de 3 manibras no invasivas: respiración única profunda, postura de pie y manibra de Valsalva. Además se investigó la secreción de amilasa de la glándula parótida como respuesta a la estimulación intraoral, ya que esta actividad enzimática es ß1-mediada de la misma manera que lo son los parámetros cardíacos citados. Los resultados obtenidos se compararon con los valores de 21 sujetos sanos jóvenes y mayores de 50 años, así como con los de 11 pacientes con cardiopatía isquémica sin tratamiento. En los pacientes jóvenes tratados con betabloqueantes se encontró que la respuesta cronotrópica estaba reducida un 60% cuando se comparó con el subgrupo cano de igual edad, pero sólo un 20% con respecto a pacientes no tratados. En los pacientes mayores de 50 años tratados con betabloqueantes, la respuesta cronotrópica fue tan sólo un 20% menor que la del subgrupo control correspondiente y sin diferencias estadísticamente significativas cuando se comparó con los pacientes sin tratamiento de igual edad. La respuesta inotrópica mostró un decrecimiento mayor aún en los pacientes jóvenes betabloqueados (75%), con respecto al subgrupo control sano y 64% cuando se comparó con el subgrupo de pacientes no tratados. En los pacientes mayores de 50 años que recibían betabloqueantes se obtuvo una reducción de la respuesta inotrópica del 53% con respecto alsubgrupo control, pero la diferencia fue nula cuando se comparó con los pacientes de igual edad si tratamiento. Esta disimilitud de respuesta según edad y cardiopatía previa obtenida con las 3 maiobras, no se presentó al estudiar la amilasa parotídea con la que se obtuvo una reducción de 50%, tanto en jóvenes como en mayores de 50 años tratados con betabloqueantes, cuando se compararon con los subgrupos control o con los datos de pacientes sin tratamiento. Esto puede atribuirse a la relativa simplicidad del arco reflejo responsable de la secreción de amilasa parotídea cuando se compara con la complejidad de las respuestas integradas cardiopulmonares. Los 3 tests empleados permiten conocer aspectos del bloqueo ß-adrenérgico hasta ahora no suficientemente jerarquizados, y pueden proponerse para estudios de seguimiento longitudinal (AU)

Physiological role of alpha-adrenoceptors in salivary secretion

The submaxillary gland (SM) of rat is innervated by both branches of the autonomic nervous system. Secretion is mediated by the activation of both muscarinic-cholinergic and alpha/beta adrenergic receptors. Studies of the relative affinity of pharmacological agonists and antagonists have warranted a subclassification of alpha adrenoceptors into types alpha 1 and alpha 2. Our studies involve an analysis of the physiologic role of both types of alpha adrenoceptors in salivary secretion. Dose response curves (DRC) to noradrenaline (NA) following administration of alpha adrenoceptor antagonists, i.e. prazosin (alpha 1 antagonist), yohimbine (alpha 2 antagonist) and phentolamine (alpha 1-alpha 2 antagonist) were constructed. Our results demonstrate that prazosin is 100 times more effective than yohimbine in blocking NA-induced salivary secretion. The alpha 2 agonist clonidine (10 micrograms/Kg) blocked the DRCs to methacholine, noradrenaline and substance P-but failed to modify the DRC to isoproterenol. Our results reveal that the subtypes of alpha adrenergic receptors play antagonistic roles in salivary secretion. Alpha 1 stimulation elicits profuse salivary secretion whereas alpha 2 stimulation inhibits salivary secretion induced by 3 different types of agonists, i.e. alpha 1, muscarinic-cholinergic and neurokininergic without affecting beta receptor mediated responses.

Physiological role of alpha-adrenoceptors in salivary secretion.

The submaxillary gland (SM) of rat is innervated by both branches of the autonomic nervous system. Secretion is mediated by the activation of both muscarinic-cholinergic and alpha/beta adrenergic receptors. Studies of the relative affinity of pharmacological agonists and antagonists have warranted a subclassification of alpha adrenoceptors into types alpha 1 and alpha 2. Our studies involve an analysis of the physiologic role of both types of alpha adrenoceptors in salivary secretion. Dose response curves (DRC) to noradrenaline (NA) following administration of alpha adrenoceptor antagonists, i.e. prazosin (alpha 1 antagonist), yohimbine (alpha 2 antagonist) and phentolamine (alpha 1-alpha 2 antagonist) were constructed. Our results demonstrate that prazosin is 100 times more effective than yohimbine in blocking NA-induced salivary secretion. The alpha 2 agonist clonidine (10 micrograms/Kg) blocked the DRCs to methacholine, noradrenaline and substance P-but failed to modify the DRC to isoproterenol. Our results reveal that the subtypes of alpha adrenergic receptors play antagonistic roles in salivary secretion. Alpha 1 stimulation elicits profuse salivary secretion whereas alpha 2 stimulation inhibits salivary secretion induced by 3 different types of agonists, i.e. alpha 1, muscarinic-cholinergic and neurokininergic without affecting beta receptor mediated responses.

Cambios tróficos y funcionales del páncrease, inducidos por la vaguectomía troncular crónica. / [Trophic and functional changes of the pancreas induced by chronic truncal vagotomy]

The effects of chronic truncal vagotomy on the pancreatic gland was studied in male adult Wistar rats. Two to three months after parasympathetic decentralization, the gland weight was found to be significantly increased by nearly 100

. This trophic effect is mainly due to the proliferation of young acinar cells. Concomitantly, there is a decrease of the ductular mass and of the Langerhans islets. Choline acetylase activity was decreased by about 35

to 40

in the vagotomized pancreas. Further, enzyme concentration was found to be greater in the head than in the body and tail of the gland, thus suggesting a higher nerve density of vagal cholinergic fibers in the former than in the latter. Basal pancreatic secretion of the decentralized gland showed a significant increase in the flow rate with no significant changes in both bicarbonate concentration and output. Protein concentration was significantly reduced at 60 minutes; protein output remained unchanged. The most remarkable finding was the fall in both lipase concentration and output (60-70

) when compared with control values. These findings may be related to clinical manifestations after long-term vagotomy.