Functional mapping of the cardiorespiratory effects of dorsal and median raphe nuclei in the rat
| Autor: | R M Alvarenga, J.G.P. Pires, H.A. Futuro Neto |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Male
medicine.medical_specialty Median raphe nucleus Respiratory rate Mediodorsal Thalamic Nucleus Physiology Immunology Biophysics Sympathetic nerve activity Glutamic Acid Stimulation Blood Pressure Biochemistry Dorsal raphe nucleus Heart Rate Internal medicine Heart rate medicine Animals General Pharmacology Toxicology and Pharmaceutics Rats Wistar Microinjection lcsh:QH301-705.5 Neurons lcsh:R5-920 Brain Mapping Raphe Chemistry General Neuroscience Respiration Cell Biology General Medicine Electric Stimulation Rats Endocrinology lcsh:Biology (General) Anesthesia Blood pressure Respiratory Mechanics L-glutamate Raphe Nuclei Raphe nuclei lcsh:Medicine (General) |
| Zdroj: | Brazilian Journal of Medical and Biological Research, Vol 38, Iss 11, Pp 1719-1727 (2005) Brazilian Journal of Medical and Biological Research, Volume: 38, Issue: 11, Pages: 1719-1727, Published: NOV 2005 Brazilian Journal of Medical and Biological Research v.38 n.11 2005 Brazilian Journal of Medical and Biological Research Associação Brasileira de Divulgação Científica (ABDC) instacron:ABDC |
| ISSN: | 0100-879X |
| Popis: | The dorsal (DRN) and median (MRN) raphe nuclei are important sources of serotonergic innervation to the forebrain, projecting to sites involved in cardiovascular regulation. These nuclei have been mapped using electrical stimulation, which has the limitation of stimulating fibers of passage. The present study maps these areas with chemical stimulation, investigating their influence on cardiorespiratory parameters. Urethane-anesthetized (1.2 g/kg, iv) male Wistar rats (280-300 g) were instrumented for pulsatile and mean blood pressure (MBP), heart rate, renal nerve activity, and respiratory frequency recordings. Microinjections of L-glutamate (0.18 M, 50-100 nl with 1% Pontamine Sky Blue) were performed within the DRN or the MRN with glass micropipettes. At the end of the experiments the sites of microinjection were identified. The majority of sites within the MRN (86.1%) and DRN (85.4%) evoked pressor responses when stimulated (DRN: DeltaMBP = +14.7 +/- 1.2; MRN: DeltaMBP = +13.6 +/- 1.3 mmHg). The changes in renal nerve activity and respiratory rate caused by L-glutamate were +45 +/- 11 and +42 +/- 9% (DRN; P < 0.05%), +40 +/- 10 and +29 +/- 7% (MRN, P < 0.05), respectively. No significant changes were observed in saline-microinjected animals. This study shows that: a) the blood pressure increases previously observed by electrical stimulation within the raphe are due to activation of local neurons, b) this pressor effect is due to sympathoexcitation because the stimulation increased renal sympathetic activity but did not produce tachycardia, and c) the stimulation of cell bodies in these nuclei also increases the respiratory rate. |
| Databáze: | OpenAIRE |
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