RESUMEN
Spike-triggered averaging, arterial pulse-triggered analysis, and coherence analysis were used to classify rostral dorsolateral pontine (RDLP) neurons into groups whose naturally occurring discharges were correlated to only the 10-Hz rhythm (n = 29), to only the cardiac-related rhythm (n = 15), and to both rhythms (n = 15) in inferior cardiac sympathetic nerve discharge (SND) of urethan-anesthetized cats. Most of the neurons with activity correlated to only the cardiac-related rhythm were located medial to the other two groups of neurons. The firing rates of most RDLP neurons with activity correlated to only the 10-Hz rhythm (9 of 12) or both rhythms (7 of 8) were decreased during baroreceptor reflex-induced inhibition of SND produced by aortic obstruction; thus, they are presumed to be sympathoexcitatory. The firing rates of four of seven RDLP neurons with activity correlated to only the cardiac-related rhythm increased during baroreceptor reflex activation; thus, they may be sympathoinhibitory. We conclude that the RDLP contains a functionally heterogeneous population of neurons with sympathetic nerve-related activity. These neurons could not be antidromically activated by stimulation of the thoracic spinal cord.
Asunto(s)
Neuronas/fisiología , Puente/fisiología , Sistema Nervioso Simpático/fisiología , Animales , Barorreflejo/fisiología , Gatos , Estimulación Eléctrica , Electrofisiología , Sistema de Conducción Cardíaco/fisiología , Puente/citología , Médula Espinal/fisiologíaRESUMEN
The current study was designed to test the hypothesis that pontine neurons are elements of the network responsible for the 10-Hz rhythm in sympathetic nerve discharge (SND). The first series of experiments tested whether chemical inactivation of neurons in the rostral dorsolateral pons (RDLP) or caudal ventrolateral pons (CVLP) affected inferior cardiac postganglionic SND of urethan-anesthetized cats. Muscimol microinjections into either region eliminated the 10-Hz rhythm in SND, supporting the view that pontine neurons are involved in the expression of this rhythm. Additional experiments were designed to determine if pontine neurons have activity correlated to the 10-Hz rhythm in SND or whether they merely provide a tonic (nonrhythmic) driving input to the rhythm generator. Coherence analysis revealed that local field potentials recorded from the RDLP or CVLP had a 10-Hz component that was significantly correlated to SND. Also, spike-triggered averaging and coherence analysis showed that the naturally occuring discharges of individual RDLP or CVLP neurons were correlated to the 10-Hz rhythm in SND. Taken together, these data support the hypothesis that RDLP and CVLP neurons are essential for the expression of the 10-Hz rhythm in SND and that they are elements of or receive input from the rhythm generator.
Asunto(s)
Red Nerviosa/fisiología , Neuronas/fisiología , Periodicidad , Puente/fisiología , Sistema Nervioso Simpático/fisiología , Potenciales de Acción/fisiología , Animales , Gatos , Electroencefalografía , Electrofisiología , Microinyecciones , Muscimol/farmacología , Neuronas/efectos de los fármacos , Puente/citología , Puente/efectos de los fármacosRESUMEN
The CT findings of adenocarcinoma of the urachus in three patients were reviewed and correlated with pathologic features. The tumor was composed of two parts: supravesical and intravesical. The supravesical portion showed a cystic appearance with a capsule in the space of Retzius. The intravesical portions invading the dome of the bladder were polypoid and unencapsulated. These findings were consistent with pathologic findings in all three patients.