Neuroscience 2004 Abstract
| Presentation Number: | 889.1 |
|---|---|
| Abstract Title: | Microdialysis of R(+)-8-OH-DPAT into the medullary raphe of the rat affects ventilation, but does not change the ventilatory response to hypoxia. |
| Authors: |
Taylor, N. C.*1
; Li, A.1
; Nattie, E. E.1
1Dept. of Physiology, Dartmouth Med. Sch., Lebanon, NH |
| Primary Theme and Topics |
Homeostatic and Neuroendocrine Systems - Respiratory regulation |
| Session: |
889. Respiratory Regulation: Hypoxia and Hypercapnia Poster |
| Presentation Time: | Wednesday, October 27, 2004 8:00 AM-9:00 AM |
| Location: | San Diego Convention Center - Hall A-H, Board # LL23 |
| Keywords: | 5HT1A RECEPTOR, BRAINSTEM, BODY TEMPERATURE |
Serotonin-containing neurons within the medullary raphe are activated as a result of hypoxia, and non-specific lesions of this area increases the ventilatory response to 7% O2 in unanesthetized rats. We found that microdialysis of the 5HT1A agonist R(+)-8-hydroxy-2(di-n-propylamino)tetralin (DPAT) into the medullary raphe decreases the ventilatory response to hypercapnia in conscious rats (SFN abstract 826.6, 2003). Here we ask whether decreasing serotonergic activity in the medullary raphe by microdialysis of DPAT affects the ventilatory response to hypoxia. Eight adult rats were surgically implanted with EEG/EMG electrodes, abdominal temperature probes, and microdialysis guide tubes in the medullary raphe. Following recovery, rats were microdialyzed on separate days with either artificial cerebrospinal fluid (aCSF) or 30 mM DPAT throughout the protocol beginning 30 minutes before the onset of recording. We measured ventilation (whole body plethysmography) during room air (30 min), 10% O2 (1 hr), and recovery room air (30 min). DPAT microdialysis increased frequency and decreased tidal volume during normoxic and hypoxic conditions in quiet wakefulness (p<0.01, two-way ANOVA), such that there was no difference in ventilation compared to aCSF microdialysis. DPAT treatment also did not affect the change in ventilation induced by 10% O2. DPAT treatment significantly decreased core body temperature by 0.2-0.4 °C compared to aCSF, corroborating previous studies (p<0.01, two-way ANOVA); but the anapyrexic response to hypoxia was unaffected by treatment. We conclude that activation of somatodendritic 5HT1A receptors in the medullary raphe does not alter the ventilatory response to hypoxia, but does alter ventilation. It remains to be determined which neuronal populations in the medullary raphe modulate the ventilatory response to hypoxia.
Supported by NIH HL 28066, and the Albert J. Ryan Foundation
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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