Inhibition of visceral pain by electrical stimulation of the periaqueductal gray matter

Pain ◽  
1976 ◽  
Vol 2 (1) ◽  
pp. 43-48 ◽  
Author(s):  
Glenn J. Giesler ◽  
John C. Liebeskind
Keyword(s):  
Electrical Stimulation ◽  
Gray Matter ◽  
Visceral Pain ◽  
Periaqueductal Gray ◽  
Periaqueductal Gray Matter ◽  
Stimulation Of

Target site of inhibition mediated by midbrain periaqueductal gray matter of baroreflex vagal bradycardia

1993 ◽  
Vol 70 (6) ◽  
pp. 2205-2214 ◽  
Author(s):  
K. Inui ◽  
S. Nosaka
Keyword(s):  
Electrical Stimulation ◽  
Gray Matter ◽  
Nucleus Tractus Solitarius ◽  
Periaqueductal Gray ◽  
Target Site ◽  
Nucleus Ambiguus ◽  
Periaqueductal Gray Matter ◽  
Preganglionic Neurons ◽  
Vagal Bradycardia ◽  
Stimulation Of

1. Both electrical and chemical stimulation of the midbrain periaqueductal gray matter (PAG) inhibit baroreflex vagal bradycardia (BVB). The present study was designed to determine the target site of this inhibition about which little is known. Electrical stimulation of the PAG, in particular of its dorsal portion, markedly suppressed BVB provoked by electrical stimulation of the aortic depressor nerve (ADN; percentage of inhibition = 91.0 +/- 9.7%, mean +/- SD; n = 64). To identify the target site of the inhibition, several types of experiments were conducted in rats under chloralose-urethan anesthesia. 2. The inhibition was exclusively of central origin because inhibition of BVB by stimulation of the PAG was unchanged after transection of the spinal cord at the C1 level. According to Wall's method, we examined whether PAG stimulation affects BVB presynaptically by modulating the excitability of ADN terminals in the nucleus tractus solitarius (NTS). However, excitability changes of ADN terminals by the PAG stimulation were not demonstrated. 3. Vagal bradycardia evoked by microinjection of glutamate into the nucleus ambiguus (NA) region was markedly suppressed by the PAG (percentage of inhibition = 85.9 +/- 9.1%; n = 9), an indication that vagal cardiac preganglionic neurons at this site were subject to the inhibitory action of the PAG. Basal vagal tone due to ongoing preganglionic neuronal activity was also subject to inhibitory control by the PAG because basal heart rate was increased by stimulation of the PAG after either C1 transection or NTS lesion. 4. We found that PAG stimulation suppressed ADN-induced field potentials in the NA region (37.7 +/- 13.8% relative to the control; n = 9) but only slightly in the NTS region (95.8 +/- 15.2%; n = 16). In addition, unitary recordings revealed that ADN-evoked unitary responses of neurons in the NA region were suppressed by PAG stimulation, whereas NTS baroreceptor neurons, either ADN responsive or nonresponsive, were scarcely inhibited by PAG stimulation. 5. These findings suggest that the PAG inhibited BVB mainly at the vagal preganglionic cell level and not at the NTS interneuron level. The conclusion is in harmony with our previous reports that the target site of hypothalamic inhibition of BVB in rats is also the preganglionic neurons and that hypothalamic inhibition of BVB is mediated predominantly by the PAG.

Methimazole-induced hypothyroidism inhibits the panic-like behaviors produced by electrical stimulation of dorsal periaqueductal gray matter of rats

2010 ◽  
Vol 35 (5) ◽  
pp. 706-716 ◽  
Author(s):  
Carla Coelho Siqueira ◽  
Renzo Roldi Rossoni ◽  
Ana Neide Carleti Pereira Tiengo ◽  
Sérgio Tufik ◽  
Luiz Carlos Schenberg
Keyword(s):  
Electrical Stimulation ◽  
Gray Matter ◽  
Periaqueductal Gray ◽  
Periaqueductal Gray Matter ◽  
Dorsal Periaqueductal Gray ◽  
Stimulation Of

Intranasal dopamine attenuates fear responses induced by electric shock to the foot and by electrical stimulation of the dorsal periaqueductal gray matter

2019 ◽  
Vol 33 (12) ◽  
pp. 1524-1532 ◽  
Author(s):  
Milene Cristina de Carvalho ◽  
Rebeca Machado de Figueiredo ◽  
Norberto Cysne Coimbra ◽  
Christie Ramos Andrade Leite-Panissi ◽  
Maria Angélica de Souza Silva ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Gray Matter ◽  
Electric Shock ◽  
Conditioned Fear ◽  
Periaqueductal Gray ◽  
Male Rats ◽  
Periaqueductal Gray Matter ◽  
Dorsal Periaqueductal Gray ◽  
Stimulation Of

Purpose: Intranasally applied dopamine (IN-DA), which likely reaches the brain via nasal–brain pathways and bypasses the blood–brain barrier, has been found to increase extracellular DA and bind to the DA2 transporter in the striatum. Recent studies suggest that DA plays a significant role in the processing of signaled and unconditioned aversive stimulation, including evidence that may attenuate responses to painful input. The purpose of this study was to examine the effects of IN-DA on fear-related behaviors induced by electric shock to the foot or by electrical stimulation of the dorsal periaqueductal gray matter (dPAG). Methods: DA hydrochloride suspended in a viscous castor oil gel (1 or 2 mg/kg) was applied (IN-DA) in a volume of 5 μL into the nostrils of adult Wistar male rats in order to evaluate its effects on (a) freezing induced by electric shock to the foot and (b) thresholds of freezing and escape and duration of post-stimulation freezing induced by electrical stimulation of the dPAG. Results: IN-DA attenuated freezing induced by electric shock to the foot in the three test trials, indicating that it reduced long-term fear responses. IN-DA also increased the threshold of dPAG stimulation-induced escape responses and reduced post-stimulation freezing. Conclusions: IN-DA, which has previously been shown to facilitate learning and to have antidepressive-like effects, attenuated unconditioned fear responses elicited by peripheral and intramesencephalic (dPAG) stimulation and reduced long-term conditioned fear responses.

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