Effects of insulin on the cardiovascular integrating mechanisms of brain stem in cats
| Autor: | L. R. Shian, J. H. Hsieh, C. Y. Chai, H. T. Horng, W. C. Wu, S. W. Kuo |
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| Rok vydání: | 1993 |
| Předmět: |
Male
medicine.medical_specialty Physiology Endocrinology Diabetes and Metabolism medicine.medical_treatment Blood Pressure Stimulation Cardiovascular System Periaqueductal gray Injections Cardiovascular Physiological Phenomena Heart Rate Physiology (medical) Internal medicine Animals Insulin Medicine Medulla Injections Intraventricular Brain Mapping business.industry Paramedian reticular nucleus Brain Electrophysiology Endocrinology Dorsal motor nucleus Injections Intravenous Parvocellular reticular nucleus Cats Locus coeruleus Female business Brain Stem |
| Zdroj: | American Journal of Physiology-Endocrinology and Metabolism. 265:E609-E616 |
| ISSN: | 1522-1555 0193-1849 |
| DOI: | 10.1152/ajpendo.1993.265.4.e609 |
| Popis: | In 65 cats anesthetized with alpha-chloralose and urethane, the effects of insulin on cardiovascular responses to stimulation of various structures in the brain stem were studied. The threshold dose of insulin injected intravenously that produced systemic hypoglycemia was 5-10 U/kg. Subthreshold hypoglycemic doses of insulin were used intracerebroventricularly (0.25 U/kg) or intracerebrally (2 mU in 200 nl). Sixty minutes after intravenous insulin, when serum glucose concentrations decreased from 158 to 43 mg/100 ml, pressor responses to stimulation of the periaqueductal gray of midbrain (PAG), locus coeruleus (LC), dorsal medulla (DM), ventrolateral medulla (VLM), and parvocellular reticular nucleus (PVC) decreased significantly. Depressor and bradycardiac response to stimulation of paramedian reticular nucleus or dorsal motor nucleus of vagus (DMV) decreased significantly as well. Thirty minutes after intracerebroventricular insulin, pressor responses of PAG, DM, and the bradycardiac response of DMV decreased significantly. Thirty minutes after intracerebral insulin, pressor responses and renal nerve activities of LC (but not PAG), VLM, DM, and PVC decreased significantly. A similar but faster onset (5 min) of depression of cardiovascular responses on stimulating the LC, VLM, DM, and PVC was observed in another six acutely midcollicular-decerebrate cats recovered from halothane anesthesia. These findings suggest that insulin directly inhibits the vasomotor structures of the brain stem and decreases the pressor responses to stimulation. |
| Databáze: | OpenAIRE |
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