Evidence for a histaminergic input from the ventral tuberomammillary nucleus to the solitary tract nucleus involved in arterial pressure regulation

• Published in: Physiological reports 2017-03, Vol.5 (5), p.np-n/a
• Main Authors: Yamanaka, Ko, Gouraud, Sabine S., Takagishi, Miwa, Kohsaka, Akira, Maeda, Masanobu, Waki, Hidefumi
• Format: Article
• Language: English
• Subjects: Animals; Arousal; Arterial pressure; Arterial Pressure - drug effects; Bicuculline; Bicuculline - pharmacology; Blood Pressure; Cardiovascular system; Cellular and Molecular Neuroscience; Central Nervous System; Cetirizine; Cetirizine - pharmacology; Electrical stimuli; Exercise; Experiments; Fitness equipment; GABA-A Receptor Antagonists - pharmacology; Heart; Heart rate; Heart Rate - drug effects; Histamine; Histamine H1 Antagonists - pharmacology; Hypothalamic Area, Lateral - drug effects; Hypothalamus; Hypothalamus (lateral); Laboratory animals; Male; Microinjection; Neural Pathways - drug effects; Neurons - drug effects; nucleus tractus solitarius; Original Research; Physical fitness; Physiology; Rats; Rats, Wistar; Running; Solitary Nucleus - drug effects; Solitary tract nucleus; Studies; Tuberomammillary nucleus; γ-Aminobutyric acid A receptors
• ISSN: 2051-817X; 2051-817X
• DOI: 10.14814/phy2.13095

The tuberomammillary nucleus (TMN) of the posterior hypothalamus has a high density of histaminergic neurons, the projection fibers of which are present in many areas of the brain, including the nucleus tractus solitarius (NTS), which controls arterial pressure (AP). In this study, we investigated whether the TMN–NTS pathway is involved in central cardiovascular regulation. Bicuculline, a gamma‐aminobutyric acid type A (GABAA) receptor antagonist, was microinjected into the ventral TMN of anesthetized rats and its effects on AP and heart rate (HR) were observed. We also evaluated the effect of cetirizine, an H1 receptor antagonist, microinjected into the NTS on cardiovascular responses induced by electrical stimulation of the TMN. Both AP and HR increased following bicuculline microinjection into the ventral TMN. Similar pressor and tachycardic responses were observed after electrical stimulation of the ventral TMN. Microinjection of cetirizine into the NTS partially inhibited the pressor response but had no effect on HR. Finally, the treadmill test was associated with a high level of c‐Fos expression in both ventral TMN and NTS neurons. These results suggest that the TMN–NTS pathway is involved in regulation of AP, presumably under a high‐arousal phase, such as that during exercise. We investigated whether the TMN–NTS pathway is involved in central cardiovascular regulation. We found that the neuronal pathway is involved in regulation of arterial pressure, presumably under physical activities, such as exercise.