Cardiovascular responses to microinjection of ANF into dorsal medulla of rats
| Autor: | D. J. McKitrick, F. R. Calaresu |
|---|---|
| Rok vydání: | 1988 |
| Předmět: |
Male
medicine.medical_specialty Microinjections Hypoglossal nucleus Physiology Blood Pressure Cardiovascular System Heart Rate Physiology (medical) Internal medicine medicine Animals Medulla Afferent Pathways Medulla Oblongata business.industry Solitary nucleus Spinal trigeminal nucleus Area postrema Rats Inbred Strains Anatomy Rats medicine.anatomical_structure Dorsal motor nucleus Endocrinology nervous system Medulla oblongata Trigeminal Nucleus Spinal Cuneate nucleus business Atrial Natriuretic Factor |
| Zdroj: | American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. 255:R182-R187 |
| ISSN: | 1522-1490 0363-6119 |
| DOI: | 10.1152/ajpregu.1988.255.1.r182 |
| Popis: | Atrial natriuretic factor (ANF) has been suggested as a putative neurotransmitter in central pathways involved in the control of the cardiovascular system. To investigate this possibility, 50 nl of 10(-7) M ANF were microinjected into discrete sites in the nucleus of the tractus solitarius (NTS) where baro- and chemoreceptor afferents terminate. Injections into 36 of a total of 66 sites in the NTS of paralyzed artificially ventilated Wistar rats under urethan anesthesia were found to produce a significant decline in heart rate [HR; -9.2 +/- 2.9 (SE) beats/min, P less than 0.05] and mean arterial pressure [MAP; -11.1 +/- 1.2 (SE) mmHg, P less than 0.01]. Similar responses were also present in anesthetized animals breathing spontaneously. Microinjection of an inactive peptide analogue or of saline did not produce cardiovascular changes. It was also found that ANF injection into the cuneate nucleus (20 of 38 sites) and the spinal trigeminal complex (28 of 42 sites) produced a decrease in MAP and HR that were of the same magnitude as those seen in the NTS. Injections of ANF into the medial longitudinal fasciculus (n = 22), hypoglossal nucleus (n = 9), area postrema (n = 16), and dorsal motor nucleus of the vagus (n = 11) did not change HR or MAP. These results suggest that ANF may serve as a neurotransmitter involved in cardiovascular reflexes mediated by specific nuclei in the dorsal medulla. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|