Connectivity and neuromodulation in the ferret paratracheal ganglion.

Format:

Book

Thesis/Dissertation

Author/Creator:

Alkon, Julian Huld.

Contributor:

Coburn, Ronald F., 1931- advisor.

University of Pennsylvania.

Language:

English

Subjects (All):

Physiology.

0433.

Penn dissertations--Physiology.

Physiology--Penn dissertations.

Local Subjects:

Penn dissertations--Physiology.

Physiology--Penn dissertations.

0433.

Physical Description:

176 pages

Contained In:

Dissertation Abstracts International 54-12B.

System Details:

Mode of access: World Wide Web.

text file

Summary:

Our understanding of connectivity in the ferret paratracheal ganglion, particularly the sites of synapses in motor pathways is in need of further development. Our knowledge of processes modulating neurotransmission, especially the extent of sympathetic neural input to the paratracheal ganglion is also in need of development. Neurotransmission from the vagus to cells in airway ganglia can be blocked by perfusion with norepinephrine. The site(s) where NOR is acting are not known, nor has it been established that there is endogenous norepinephrine which can modulate neurotransmission. We used a suction electrode to record from ganglia associated with the longitudinal nerve trunk (LNT) of the paratracheal ganglion. The LNT was electrically stimulated and evoked potentials were recorded over distances of more than 20 mm. Neurons carrying the signal in the LNT were found to be electrically homogeneous. Perfusing the preparation with low Ca$\sp{2+}$/high Mg$\sp{2+}$ Krebs had little or no effect on the amplitude of potentials evoked at short distances, while at distances between 8 and 20 mm potentials were decreased to 38% of controls. Treatment of the tissue with glyoxylic acid revealed catecholamines in nerves and blood vessels, including some running close ($<$50 uM) to the LNT. The tissue was perfused with yohimbine, which potentiates secretion of norepinephrine from sympathetic neurons, with desipramine, which inhibits the reuptake of norepinephrine, or with a combination of the two. Train stimulation at 3 Hz. produced significant decreases in the amplitude of evoked potentials: with yohimbine to 43 $\pm$ 6%, with desipramine to 58 $\pm$ 11% and with yohimbine + desipramine to 30 $\pm$ 10% of control (all S.E.M.s). With yohimbine, alone or in combination with desipramine, the decreases were train-dependent. The major conclusions were that signals travelling in the LNT more than approximately 6-8 mm traverse a synapse, and that endogenous catecholamines can be released by nerve stimulation to block neurotransmission at these sites.

Notes:

Thesis (Ph.D. in Physiology) -- Graduate School of Arts and Sciences, University of Pennsylvania, 1993.

Source: Dissertation Abstracts International, Volume: 54-12, Section: B, page: 6084.

Supervisor: Ronald F. Coburn.

Local Notes:

School code: 0175.

Access Restriction:

Restricted for use by site license.