Differential effects of serotonergic and peptidergic cardioexcitatory neurons on the heart activity in the pteropod mollusc, Clione limacina |
| |
Authors: | A Y Malyshev T P Norekian A O D Willows |
| |
Institution: | (1) Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow 117865, Russia, RU;(2) Department of Biology, Arizona State University, Tempe, AZ 85287-1501, USA e-mail: Tigran.Norekian@ASU.EDU Fax: +1-602-965-2519, US;(3) Friday Harbor Laboratories, University of Washington, Seattle, WA 98250, USA, US |
| |
Abstract: | A group of four cardioexcitatory neurons has been identified in the intestinal ganglia of the mollusc Clione limacina. Relatively weak stimulation of the intestinal neurons induced auricle contractions only, while strong stimulation produced
initial auricle contractions followed by full-cycle auricle-ventricle contractions. Intestinal cardioexcitatory neurons probably
utilized as their transmitter a peptide similar to Tritonia pedal peptide – they showed pedal peptide-like immunoreactivity, and their effects were mimicked by application of the exogenous
pedal peptide. The pedal cardioexcitatory neuron was found to produce strong excitatory effects only on the ventricle contractions.
Its stimulation induced ventricle contractions in the quiescent heart or significantly accelerated the rate of ventricle contractions
in the rhythmically active heart. The pedal cardioexcitatory neuron apparently utilized serotonin as a neurotransmitter, based
upon serotonin immunoreactivity, blocking effect of serotonin antagonists mianserin and methysergide, and the observation
that exogenous serotonin mimicked its effect. A dense network of pedal peptide-like immunoreactivity was found both in the
auricle and ventricle tissue. Serotonin immunoreactivity was densely present in the ventricle, while the auricle contained
only a separate serotonin-immunoreactive unbranched axon. Thus, there are two separate groups of central cardioexcitatory
neurons with different effects on heart activity, which together might provide a complex cardio-regulatory function in Clione.
Accepted: 14 August 1999 |
| |
Keywords: | Heart control Cardioexcitatory neuron Serotonin Peptide Mollusc |
本文献已被 SpringerLink 等数据库收录! |
|