Glutamate and GABA in the medial amygdala induce selective central sympathetic/parasympathetic cardiovascular responses

Neckel, Helinton; Quagliotto, Édson; Casali, Karina Rabello; Montano, Nicola; Lago, Pedro Dal; Rasia‐Filho, Alberto A.

doi:10.1139/y2012-024

Cited by 23 publications

(33 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…18,28 The lack of effect of MeAm lesions on BP in BPN/3J mice supports these prior findings in normotensive animals but the same was not true in hypertensive BPH/2J mice. It is interesting to note that there were greater Fos counts in the BLA after stress in BPH/2J mice with MeAm lesions but not in BPN/3J mice.…”

Section: Discussionsupporting

confidence: 78%

“…The MeAm has been demonstrated previously to mediate phasic changes in cardiovascular parameters during stress, chemoreflex, and baroreflex activation. 18,28 However, acute inhibition of the MeAm in normotensive rats has consistently demonstrated no effect on resting BP, indicating that neurons in this region are unlikely affecting tonic levels of BP. 18,28 The lack of effect of MeAm lesions on BP in BPN/3J mice supports these prior findings in normotensive animals but the same was not true in hypertensive BPH/2J mice.…”

Section: Discussionmentioning

confidence: 99%

“…18,28 However, acute inhibition of the MeAm in normotensive rats has consistently demonstrated no effect on resting BP, indicating that neurons in this region are unlikely affecting tonic levels of BP. 18,28 The lack of effect of MeAm lesions on BP in BPN/3J mice supports these prior findings in normotensive animals but the same was not true in hypertensive BPH/2J mice. It is interesting to note that there were greater Fos counts in the BLA after stress in BPH/2J mice with MeAm lesions but not in BPN/3J mice.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Major Contribution of the Medial Amygdala to Hypertension in BPH/2J Genetically Hypertensive Mice

et al. 2014

View full text Add to dashboard Cite

BPH/2J mice are a genetic model of hypertension developed in the 1970s by Schlager et al.1 These mice were selectively bred for elevated blood pressure (BP) alongside a normotensive (BPN/3J) and hypotensive control strain (BPL/1J), from a base population of 8 inbred strains of mice. Since then a range of pathophysiological factors have been studied to determine the cause of hypertension in BPH/2J mice, and the relatively modest characterization has been increasing in recent years, possibly because of advances in technology used to study mice. 2,3 Our own findings suggest that hypertension in BPH/2J mice is sympathetically mediated, based on the greater depressor response to ganglion blockade, which ultimately abolishes the hypertension in BPH/2J mice and also greater midfrequency mean arterial pressure variability (MAP power). 4 Even the percentage depressor response to ganglion blockade is greater in BPH/2J mice compared with normotensive controls. 4 This contrasts findings in spontaneously hypertensive rats (SHRs) that are likely confounded by a vascular amplifier effect 5 caused by vascular structural changes, which contribute to hypertension in adult SHRs. 6 Recently, we have also reported that BPH/2J mice have renal sympathetic hyperinnervation and enhanced renin synthesis, which results in a greater contribution of the renin-angiotensin system (RAS) to BP maintenance during the dark period of the 24-hour light cycle in BPH/2J mice compared with BPN/3J mice. 7 Early studies indicated that BPH/2J mice have aberrant brain catecholamine levels, 8 suggesting that the hypertension may be centrally mediated. Furthermore, using Fos as a marker of neuronal activity, BPH/2J mice were also shown to have greater neuronal activity in key cardiovascular regulatory brain regions compared with normotensive control BPN/3J mice. 4 Importantly, of the limbic, hypothalamic, and medullary brain regions analyzed using Fos immunohistochemistry, the medial amygdala (MeAm) was the only region to show greater neuronal activity during the light (inactive) and the dark (active) period in BPH/2J compared with BPN/3J mice, 4 suggesting that this region may be inherently overactive in BPH/2J mice. Furthermore, neuronal activity within the MeAm correlated strongly with BP level (R=0.98), suggesting that neuronal activity in the MeAm may be related to BP level. 4 The MeAm is an important limbic region that integrates sensory information, including stress and fear as well as reproductive-related inputs, and regulates the subsequent cardiovascular, behavioral, and hormonal responses.9-11 The MeAm is activated by stressful stimuli particularly of psychological rather than a physiological nature 12 and is involved Abstract-BPH/2J mice are recognized as a neurogenic model of hypertension primarily based on overactivity of the sympathetic nervous system and greater neuronal activity in key autonomic cardiovascular regulatory brain regions. The medial amygdala (MeAm) is a forebrain region that integrates the autonomic response...

show abstract

Section: Discussionsupporting

confidence: 78%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Major Contribution of the Medial Amygdala to Hypertension in BPH/2J Genetically Hypertensive Mice

et al. 2014

View full text Add to dashboard Cite

show abstract

“…The upper plateau was calculated by the sum of P 1 and P 2 (Quagliotto et al, 2008;Neckel et al, 2012).…”

Section: Groupsmentioning

confidence: 99%

Chronic electroacupuncture of the ST36 point improves baroreflex function and haemodynamic parameters in heart failure rats

Lima

Hentschke

Rossato

et al. 2015

Autonomic Neuroscience

View full text Add to dashboard Cite

“…The nucleus also modulates basic motor and autonomic function (Homma and Masaoka, 2008;Quagliotto et al, 2008;Neckel et al, 2012;Quagliotto et al, 2015; Figure 6.6: A) A representation of integrated motor and autonomic changes generated by stimulating the ventral hippocampus with DLH (200 nL) prior to inactivation of the amygdala. B) Representative photomicrograph of DLH injection site in the ventral hippocampus.…”

Section: Discussionmentioning

confidence: 99%

Limbic modulation of the autonomic nervous system

Ajayi¹

View full text Add to dashboard Cite

Nuclei in the hypothalamus and brainstem are responsible for maintaining homoeostasis by controlling rhythmic motor and autonomic activities. However, during emotional responses to real or potential environmental challenges, significant changes in motor and autonomic rhythm also occur.Forebrain structures that form the limbic system are responsible for perceiving environmental challenges and orchestrating appropriate emotional responses. Thus, it is only through descending synaptic interactions of the forebrain areas with the hypothalamus and brainstem, that modulation of motor and autonomic activities is possible during the expression of emotions. However, there is little knowledge of the forebrain areas that modulate autonomic activities. Also, in coordinating physiologic responses, forebrain structures operate through functional networks but the neural pathways and mechanisms involved particularly during emotional behaviours are not clear.The hippocampus is an important component of the limbic system involved in learning and memory, but evolving evidence implicates it in the expression of emotions such as defensive fear and anxiety reactions. Studies also suggest possible hippocampal connections with brainstem autonomic centres.Thus, the central hypothesis tested in this thesis is that discrete neurone populations in the ventral hippocampus, via neuronal projections to the amygdala, can modulate bulbar motor and autonomic output. Specific aims were to 1) Investigate and describe the respiratory and cardiovascular changes induced by chemically mapping the dorsal and ventral hippocampus with microinjections of the excitatory amino acid, D, L-Homocysteic acid, 2) Investigate the distribution of descending projections of the hippocampus using classical neuroanatomical tract tracing techniques, with a particular focus on the connectivity of the ventral hippocampus and the amygdala, 3) To extend the chemical mapping to specific areas in the amygdala that receive projections from the hippocampus and determine how such areas differ in their influence over motor and autonomic functions and 4) To investigate the effects of inhibiting of the amygdala while stimulating the ventral hippocampus.Experiments were conducted using urethane-anaesthetised (1.5 g/kg IP) adult Sprague-Dawley rats (n = 136; weight = 300 -600 g; either sex). The hippocampus was stereotaxically mapped to locate discrete neurone populations that can modulate motor and autonomic activities. The specific parameters monitored include blood pressure, heart rate, respiratory frequency, inspiratory and expiratory durations, tracheal pressure and the motor expression of augmented breaths.Microinjections of the excitatory amino acid (EAA), D, L, Homocysteic acid (DLH; 50 mM, pH 7.4, iii n = 95), were used for chemical stimulation. Using this stimulation technique, discrete neurone populations in the ventral hippocampus were identified that can generate significant changes in both respiratory and cardiovascular parameters. Augmented breaths, which have...

show abstract

Glutamate and GABA in the medial amygdala induce selective central sympathetic/parasympathetic cardiovascular responses

Cited by 23 publications

References 61 publications

Major Contribution of the Medial Amygdala to Hypertension in BPH/2J Genetically Hypertensive Mice

Major Contribution of the Medial Amygdala to Hypertension in BPH/2J Genetically Hypertensive Mice

Chronic electroacupuncture of the ST36 point improves baroreflex function and haemodynamic parameters in heart failure rats

Limbic modulation of the autonomic nervous system

Contact Info

Product

Resources

About