RESUMO
The number of myenteric neurons may be reduced by topical serosal application of benzalkonium chloride (BAC). We studied the effects of ageing in the population of neurons that survive after the application of BAC. Ten treated and ten control animals were killed at intervals of 2, 6, 12 and 18 months after the surgery. We performed myenteric neurons counting in serially cut histological preparations of the descending colon. The control animals revealed a continuous loss of myenteric neurons number with increasing of age. Interestingly, contrary to control animals, the BAC-treated rats presented no neuron loss with ageing at any experimental time. The reasons for their survival with ageing could be related to a neuroplasticity phenomenon.
Assuntos
Envelhecimento , Compostos de Benzalcônio/farmacologia , Plexo Mientérico/efeitos dos fármacos , Neurônios/citologia , Neurônios/efeitos dos fármacos , Animais , Contagem de Células , Colo Sigmoide/efeitos dos fármacos , Colo Sigmoide/inervação , Masculino , Plexo Mientérico/citologia , Ratos , Ratos WistarRESUMO
Diphenylhydantoin (DPH) induced changes in distal colon motility in the 37 subjects investigated. In subjects with sigmoidal hyperactivity plus rectal hypoactivity, DPH suppressed or reduced sigmoidal phasic activity. In subjects showing no sigmoidal activity predominance, DPH induced increases of sigmoidal and/or rectal motility. Sulpiride (an "atypical" dopaminergic blocking agent) antagonized DPH-induced changes. Our results strongly suggest that DPH-induced distal motility changes are mediated by the dopaminergic and noradrenergic systems.
Assuntos
Colo/fisiologia , Motilidade Gastrointestinal/efeitos dos fármacos , Fenitoína/farmacologia , Adulto , Colo/efeitos dos fármacos , Colo Sigmoide/efeitos dos fármacos , Colo Sigmoide/fisiologia , Feminino , Haloperidol/farmacologia , Humanos , Masculino , Manometria , Fenitoína/antagonistas & inibidores , Reto/efeitos dos fármacos , Reto/fisiologia , Sulpirida/farmacologiaRESUMO
Motor activity of the lower bowel was induced by the parenteral administration of prostigmine or bethanechol in 7 subjects. Intraluminal pressure recordings from the sigmoid colon and rectum revealed that the augmented responses of motor activity to these cholinomimetic drugs were similar both in duration and in motility indexes. The intravenous administration of glucagon inhibited the motor responses to both cholinomimetic stimuli employed. A possible mechanism for the inhibitory action of glucagon is suggested and the clinical application of these observations is discussed.