Experiments were carried out to determine the influence of sympathetic stimulation on the activity of atrial fibers. Type B atrial fibers were dissected from slips of the cervical vagus in open chest dogs. Atrial contractility was monitored using a strain gauge arch. The discharge rate of type B fibers was observed during increases in left atrial pressure induced by volume expansion. After each increment in left atrial pressure the left stellate ganglion was stimulated for 10-15 seconds (7 dogs) or norepinephrine was injected (2 dogs). Sympathetic stimulation increased atrial contractility and decreased left atrial pressure and B fiber discharge. In some instances sympathetic stimulation caused complete silencing of fiber activity. With cessation of sympathetic stimulation, atrial pressure and fiber activity increased. These experiments indicate that cardiac sympathetic efferent nerve activity modulates atrial B fiber activity through alterations in atrial pressure.
|Original language||English (US)|
|Number of pages||1|
|Issue number||3 (I)|
|State||Published - 1973|
ASJC Scopus subject areas