scholarly journals The cardiovascular responses after lipopolysaccharide microinjection into the dorsomedial periaqueductal gray in rats

2021 ◽  
Vol 25 (4) ◽  
pp. 334-340
Author(s):  
Reza Mohebbati ◽  
Reza Nejad Shahrokh Abadi ◽  
Vida Alikhani ◽  
Mohammad Naser Shafei ◽  
◽  
...  
Keyword(s):  
Cardiovascular Responses ◽  
Periaqueductal Gray

scholarly journals Amygdalar neuronal activity mediates the cardiovascular responses evoked from the dorsolateral periaqueductal gray in conscious rats

Neuroscience ◽  
2015 ◽  
Vol 284 ◽  
pp. 737-750 ◽  
Author(s):  
A.R. de Abreu ◽  
A.R. Abreu ◽  
L.T. Santos ◽  
A.A. de Souza ◽  
L.G. da Silva ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Cardiovascular Responses ◽  
Periaqueductal Gray ◽  
Conscious Rats

c-Fos expression in the midbrain periaqueductal gray during static muscle contraction

2000 ◽  
Vol 279 (6) ◽  
pp. H2986-H2993 ◽  
Author(s):  
Jianhua Li ◽  
Jere H. Mitchell
Keyword(s):  
Skeletal Muscle ◽  
Muscle Contraction ◽  
Neuronal Cells ◽  
Cardiovascular Responses ◽  
Periaqueductal Gray ◽  
Exercise Pressor Reflex ◽  
Arterial Blood ◽  
Static Contraction ◽  
Afferent Inputs ◽  
Pressor Reflex

The periaqueductal gray (PAG) of the midbrain is involved in the autonomic regulation of the cardiovascular system. The purpose of this study was to determine if static contraction of the skeletal muscle, which increases arterial blood pressure and heart rate, activates neuronal cells in the PAG by examining Fos-like immunoreactivity (FLI). Muscle contraction was induced by electrical stimulation of the L7 and S1 ventral roots of the spinal cord in anesthetized cats. An intravenous infusion of phenylephrine (PE) was used to selectively activate arterial baroreceptors. Extensive FLI was observed within the ventromedial region (VM) of the rostral PAG, the dorsolateral (DL), lateral (L), and ventrolateral (VL) regions of the middle and caudal PAG in barointact animals with muscle contractions, and in barointact animals with PE infusion. However, muscle contraction caused a lesser number of FLI in the VM region of the rostral PAG, the DL, L, and VL regions of the middle PAG and the L and VL regions of the caudal PAG after barodenervation compared with barointact animals. Additionally, the number of FLI in the DL and L regions of the middle PAG was greater in barodenervated animals with muscle contraction than in barodenervated control animals. Thus these results indicated that both muscle receptor and baroreceptor afferent inputs activate neuronal cells in regions of the PAG during muscle contraction. Furthermore, afferents from skeletal muscle activate neurons in specific regions of the PAG independent of arterial baroreceptor input. Therefore, neuronal cells in the PAG may play a role in determining the cardiovascular responses during the exercise pressor reflex.

Central integration of muscle reflex and arterial baroreflex in midbrain periaqueductal gray: roles of GABA and NO

2004 ◽  
Vol 287 (3) ◽  
pp. H1312-H1318 ◽  
Author(s):  
Jianhua Li
Keyword(s):  
Muscle Contraction ◽  
Pressor Response ◽  
Cardiovascular Responses ◽  
Periaqueductal Gray ◽  
Muscle Afferents ◽  
Triceps Surae ◽  
Reflex Response ◽  
Arterial Baroreflex ◽  
Pressor Reflex ◽  
Change In Mean

It has been suggested that the midbrain periaqueductal gray (PAG) is a neural integrating site for the interaction between the muscle pressor reflex and the arterial baroreceptor reflex. The underlying mechanisms are poorly understood. The purpose of this study was to examine the roles of GABA and nitric oxide (NO) in modulating the PAG integration of both reflexes. To activate muscle afferents, static contraction of the triceps surae muscle was evoked by electrical stimulation of the L7 and S1 ventral roots of 18 anesthetized cats. In the first group of experiments ( n = 6), the pressor response to muscle contraction was attenuated by bilateral microinjection of muscimol (a GABA receptor agonist) into the lateral PAG [change in mean arterial pressure (ΔMAP) = 24 ± 5 vs. 46 ± 8 mmHg in control]. Conversely, the pressor response was significantly augmented by 0.1 mM bicuculline, a GABAA receptor antagonist (ΔMAP = 65 ± 10 mmHg). In addition, the effect of GABAA receptor blockade on the reflex response was significantly blunted after sinoaortic denervation and vagotomy ( n = 4). In the second group of experiments ( n = 8), the pressor response to contraction was significantly attenuated by microinjection of l-arginine into the lateral PAG (ΔMAP = 26 ± 4 mmHg after l-arginine injection vs. 45 ± 7 mmHg in control). The effect of NO attenuation was antagonized by bicuculline and was reduced after denervation. These data demonstrate that GABA and NO within the PAG modulate the pressor response to muscle contraction and that NO attenuation of the muscle pressor reflex is mediated via arterial baroreflex-engaged GABA increase. The results suggest that the PAG plays an important role in modulating cardiovascular responses when muscle afferents are activated.

Sign in / Sign up

Export Citation Format

Share Document