The expression of contextual fear conditioning involves activation of a NMDA receptor-nitric oxide-cGMP pathway in the dorsal hippocampus of rats

Fabri, D.R.S.; Hott, Sara C.; Reis, Daniel G.; Biojone, Caroline; Corrêa, Fernando M.A.; Resstel, Leonardo Barbosa Moraes

doi:10.1016/j.euroneuro.2014.08.002

Cited by 23 publications

(11 citation statements)

References 57 publications

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“…When rats are later re-exposed to the context, now referred to as the conditioned stimulus, they exhibit freezing behavior and increased autonomic activity, represented by increased mean arterial pressure (MAP) and heart rate (HR) and decreased cutaneous temperature (CT) (Fabri et al, 2014;Hott et al, 2012). The behavioral and autonomic changes are collectively called conditioned emotional response (Resstel et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Dorsolateral periaqueductal gray matter CB1 and TRPV1 receptors exert opposite modulation on expression of contextual fear conditioning

et al. 2016

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Section: Introductionmentioning

confidence: 99%

Dorsolateral periaqueductal gray matter CB1 and TRPV1 receptors exert opposite modulation on expression of contextual fear conditioning

et al. 2016

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“…iNOS‐knockout mice exhibit increased autonomic responses in the contextual fear conditioning model (Lisboa et al, ). In the same way, nNOS inhibition in the DH increased the rise in the BP and HR from rats re‐exposed to an aversive context (Fabri et al, ; Spiacci, Antero, Reis, Lisboa, & Resstel, ). This cardiovascular response to the aversive context occurs together with an enhancement in NO concentration within the DH (Fabri et al, ).…”

Section: Discussionmentioning

confidence: 82%

“…In the same way, nNOS inhibition in the DH increased the rise in the BP and HR from rats re‐exposed to an aversive context (Fabri et al, ; Spiacci, Antero, Reis, Lisboa, & Resstel, ). This cardiovascular response to the aversive context occurs together with an enhancement in NO concentration within the DH (Fabri et al, ). Moreover, nNOS inhibition within the DH attenuated the autonomic responses (increment in the BP and HR and decrement in cutaneous temperature) evoked by acute restraint stress (Moraes‐Neto et al, ), suggesting that hippocampal NO plays an important role in cardiovascular responses during aversive conditions.…”

Section: Discussionmentioning

confidence: 82%

Dorsal hippocampus cholinergic and nitrergic neurotransmission modulates the cardiac baroreflex function in rats

Ferreira‐Junior

Lagatta

Kuntze

et al. 2019

Eur J of Neuroscience

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Hippocampus is a limbic structure involved in the baroreflex and chemoreflex control that receives extensive cholinergic input from basal forebrain. Hippocampal muscarinic receptors activation by acetylcholine might evoke nitric oxide synthesis, which is an important neuromodulator of cardiovascular responses. Thus, we hypothesize that cholinergic and nitrergic neurotransmission within the DH modulates the baroreflex and chemoreflex function. We have used vasoactive drugs (phenylephrine and sodium nitroprusside), and potassium cyanide infused peripherally to induce, respectively, baroreflex or chemoreflex responses in awake animals. Bilateral injection into the DH of the acetylcholinesterase inhibitor (neostigmine) reduced baroreflex responses. Meanwhile, the non‐selective muscarinic receptor antagonist (atropine) or the M1‐selective muscarinic receptor antagonist increased baroreflex responses (pirenzepine). Furthermore, the neuronal nitric oxide synthase inhibitor (N‐propyl) or the intracellular NO scavenger (carboxy‐PTIO) increased baroreflex responses, as well as the selective inhibitor of NO‐sensitive guanylyl cyclase (ODQ), increased the baroreflex responses. Besides, bilateral administration of an ineffective dose of a neuronal nitric oxide synthase inhibitor abolished the reduction in the baroreflex responses evoked by an acetylcholinesterase inhibitor. On the other hand, we have demonstrated that hippocampal cholinergic neurotransmission did not influence the chemoreflex function. Taken together, our findings suggest that nNOS‐derived nitric oxide in the DH participates in acetylcholine‐evoked baroreflex responses.

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“…Carrive et al (1997) observed an increased expression of c-FOS protein, a neuronal activity marker, in vlPAG neurons during re-exposure of rats to an aversive context (Carrive et al, 1997). Accordingly, in aversive situations there is a shift in the baroreflex set point toward higher BP values (Crestani et al, 2010), allowing concomitant increases in HR and BP, which is discriminative of such situations (Aguiar et al, 2014;Fabri et al, 2014). Furthermore, the vlPAG seems to be important not only to interfere with the HR enhancement in such situations but also to reduce the HR to the basal levels, since that inhibition of the vlPAG neurotransmission enhanced the cardiovascular responses elicited during the conditioned emotional response, and also delayed the return of HR and MAP to the resting values when those animals were placed in their home box again (Walker & Carrive, 2003).…”

Section: Discussionmentioning

confidence: 98%

Ventrolateral periaqueductal grey matter neurotransmission modulates cardiac baroreflex activity

Lagatta

Ferreira‐Junior

Deolindo

et al. 2016

Eur J of Neuroscience

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Baroreflex activity is a neural mechanism responsible for short-term adjustments in blood pressure (BP). Several supramedullary areas, which send projections to the medulla, are able to control this reflex. In this context, the ventrolateral part of the periaqueductal grey matter (vlPAG), which is a mesencephalic structure, has been suggested to regulate the cardiovascular system. However, its involvement in baroreflex control has never been addressed. Therefore, our hypothesis is that the vlPAG neurotransmission is involved in baroreflex cardiac activity. Male Wistar rats had stainless steel guide cannulae unilaterally or bilaterally implanted in the vlPAG. Afterward, a catheter was inserted into the femoral artery for BP and HR recording. A second catheter was implanted into the femoral vein for baroreflex activation. When the nonselective synaptic blocker cobalt chloride (CoCl ) was unilaterally injected into the vlPAG, in either the left or the right hemisphere, it increased the tachycardic response to baroreflex activation. However, when CoCl was bilaterally microinjected into the vlPAG it decreased the tachycardic response to baroreflex stimulation. This work shows that vlPAG neurotransmission is involved in modulation of the tachycardic response of the baroreflex. Moreover, we suggest that the interconnections between the vlPAG of both hemispheres are activated during baroreflex stimulation. In this way, our work helps to improve the understanding about brain-heart circuitry control, emphasizing the role of the autonomic nervous system in such modulation.

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The expression of contextual fear conditioning involves activation of a NMDA receptor-nitric oxide-cGMP pathway in the dorsal hippocampus of rats

Cited by 23 publications

References 57 publications

Dorsolateral periaqueductal gray matter CB1 and TRPV1 receptors exert opposite modulation on expression of contextual fear conditioning

Dorsolateral periaqueductal gray matter CB1 and TRPV1 receptors exert opposite modulation on expression of contextual fear conditioning

Dorsal hippocampus cholinergic and nitrergic neurotransmission modulates the cardiac baroreflex function in rats

Ventrolateral periaqueductal grey matter neurotransmission modulates cardiac baroreflex activity

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