Inhibition of spinal nociceptive information by stimulation in midbrain of the cat is blocked by lidocaine microinjected in nucleus raphe magnus and medullary reticular formation

Gebhart, G.F.; Sandkühler, Jürgen; Thalhammer, J. G.; Zimmermann, M.

doi:10.1152/jn.1983.50.6.1446

Cited by 147 publications

(40 citation statements)

References 8 publications

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“…Lesions of A5 reduce the antinociceptive effect of microinjecting the non-selective adrenergic antagonist phentolamine into the RVM (Proudfit, 1988) suggesting that this A5-derived NE input to RVM is involved in pain modulation. The antinociceptive effect of stimulating in the dorsolateral pontomesencephalic region, near A7, is reduced by reversible inactivation of the RVM (Gebhart et al, 1983). Although that study did not directly implicate the noradrenergic A7 neurons, its results plus the demonstrated projection of A5 and A7 neurons to both the RVM and the dorsal horn (Reichling et al, 1988;Kwiat and Basbaum, 1992) are consistent with a role for A7 projections to RVM in pain modulation.…”

Section: Source Of Th Profiles In the Rvmmentioning

confidence: 62%

Noradrenergic input to nociceptive modulatory neurons in the rat rostral ventromedial medulla

Meng

Budra²,

Skinner³

et al. 1997

J. Comp. Neurol.

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Within the rostral ventromedial medulla (RVM), there are two classes of putative pain modulation neurons: ON cells and OFF cells, which respectively burst or pause prior to withdrawal reflexes elicited by noxious stimulation. Alpha-adrenergic agonists injected into the RVM produce changes in the latency of spinal nocifensive reflexes and, when iontophoretically applied, alter the firing of RVM ON but not OFF cells. To provide further information about the contribution of norepinephrine to RVM neuron function, we analyzed the distribution of tyrosine hydroxylase immunoreactive (TH-ir) appositions upon RVM ON and OFF cells. In the lightly anesthetized rat, seven ON and five OFF cells were identified by changes in their discharge rate in relation to nociceptive withdrawal reflexes and were labeled by intracellular injection of neurobiotin. Sections containing labeled cells were visualized by using avidin conjugated to a Texas Red fluorophore. Tissue with labeled cells was subsequently processed for TH-ir by using a Bodipy fluorophore conjugated secondary antibody. The distribution of the Bodipy-labeled fibers and terminals upon the Texas Red-labeled neurons was mapped using a confocal laser-scanning microscope. All the labeled neurons exhibited close TH-ir appositions. Appositions were of two types: swellings and fibers. Although the numbers and density of appositions varied among the cells, there were no consistent differences that correlated with physiological properties. Thus the overall density of appositions for ON cells (29.0 +/- 22.2 x 10(4) microns2) did not differ significantly from that for OFF cells (25.4 +/- 22.2 x 10(4) microns2). Tyrosine hydroxylase immunoreactive (TH-ir) appositions upon ON and OFF cells varied with their location along the dorso-ventral axis with more ventral neurons having a greater density of TH-ir swelling-type appositions. In a separate study, TH-ir and dopamine-beta-hydroxylase-like immunoreactivity (DBH-ir) were mapped in the same sections by using confocal microscopy. Nearly 97% of the TH-ir profiles co-localized with DBH-ir. These observations provide evidence that both ON and OFF cells in the RVM are targeted by noradrenergic inputs.

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Section: Source Of Th Profiles In the Rvmmentioning

confidence: 62%

Noradrenergic input to nociceptive modulatory neurons in the rat rostral ventromedial medulla

Meng

Budra²,

Skinner³

et al. 1997

J. Comp. Neurol.

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“…Such antinociception is thought to result in inhibition of nociceptive neurons in the dorsal horn (Liebeskind et al, 1973), directly and via the nucleus raphe magnus of the rostral ventromedial medulla (Gebhart et al, 1983). Thus, the periaqueductal gray modulates the amount of nociceptive information which is transmitted to higher brain centres, and hence, affects the magnitude of pain experienced.…”

Section: Supraspinal Modulation Of Pain-mentioning

confidence: 99%

Nociceptive flexion reflex thresholds and pain during rest and computer game play in patients with hypertension and individuals at risk for hypertension

Edwards

Ring

Al’Absi

et al. 2007

Biological Psychology

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Supraspinal pain modulation may explain hypertensive hypoalgesia. We compared nociceptive flexion reflex (NFR) thresholds and pain during rest and computer game play in hypertensives and normotensives (Experiment 1) and normotensives with and without hypertensive parents (Experiment 2). The game was selected to modulate activity in pain pathways. NFR thresholds did not differ between groups during rest or game play. Pain ratings never differed between hypertensives and normotensives, whereas individuals with hypertensive parents reported less pain during the first two NFR assessments, compared to those without. NFR thresholds and pain were reduced by game play compared to rest. The failure of game play to differentially modulate NFR thresholds or associated pain reports between groups argues against enhanced supraspinal modulation of nociception and pain in hypertensives and those at increased risk for hypertension.

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“…These results may indicate a role of MRF neurons in visceral nociception as well. It has been shown that the MRF can modulate nociceptive processing by its descending (excitatory and inhibitory) inputs (McCreery et al 1979;Haber et al 1980;Gebhart et al 1983;Zhuo & Gebhart, 1990, 2002a, and work as relay nuclei to higher centres for nociceptive processing and ultimately pain perception (Foreman et al 1984).…”

Section: Convergence Of Ub and Colon Inputs In The Mrfmentioning

confidence: 99%

Convergence of multiple pelvic organ inputs in the rat rostral medulla

Kaddumi

Hubscher

2006

The Journal of Physiology

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Electrophysiological recordings were used to investigate the degree of pelvic/visceral convergent inputs onto single medullary reticular formation (MRF) neurons. A total of 94 MRF neurons responsive to bilateral electrical stimulation of the pelvic nerve (PN) in 12 urethane-anaesthetized male rats were tested for responses to mechanical stimulation of the urinary bladder, urethra, colon and penis, and electrical stimulation of the dorsal nerve of the penis (DNP) and abdominal branches of the vagus. Responses to distension of the bladder were found for 51% (n = 48) of the MRF neurons tested. Of these 48, 71% responded to urethral infusion, 81% responded to colon distension, 100% responded to penile stimulation (and DNP), and 85% responded to vagal stimulation, with 62% responding to stimulation of all four of these territories. This high degree of visceral convergence (i.e. 62%) in a subset of PN-responsive MRF neurons is significantly greater than for the subset of PN-responsive MRF neurons that did not respond to urinary bladder distension (i.e. out of the 46 remaining neurons, none responded to all four of the other pelvic/visceral stimuli combined). These results suggest that the neurons processing information from the urinary bladder at this level of the neural axis are likely to be important for mediating interactions between different visceral organs for the coordination of multiple pelvic/visceral functions. Normal functions related to the male pelvic/visceral organs, such as urination, defaecation, and ejaculation, involve coordination between the different organ systems. One example of a process in which coordination is important is ejaculation, which consists of emission of the seminal fluid from the ejaculatory ducts to the proximal urethra, bladder neck closure and anterograde ejaculation out of the proximal urethra (Seftel et al. 1991;Truitt & Coolen, 2002). Disruption of this coordination, such as following spinal cord injury, results in the failure of bladder neck closure and thus a subsequent retrograde ejaculation leading to infertility (Heruti et al. 2001).Another example in which coordination between the pelvic organs is important is during voiding of the urinary bladder, which requires contraction of the external anal sphincter, thereby preventing defaecation. In humans, distension of the urinary bladder produces contractions of the anal sphincter (Basinski et al. 2003). Experimental studies using cats have shown that distension of the urinary bladder both inhibits colonic contractions (Bouvier et al. 1990) and produces simultaneous contraction of the anal sphincter (Bouvier & Grimaud, 1984). The reverse also occurs, i.e. the urinary system is inhibited during defaecation. In humans, functional stimulation of the anal sphincter inhibits detrusor muscle contraction (Cheng et al. 2002). In animal studies, distension of the rectum has been shown to inhibit urinary bladder activity in female rats (Sugaya et al. 1998), and stimulation of colonic branches of the pelvic nerve in cats has been shown ...

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Inhibition of spinal nociceptive information by stimulation in midbrain of the cat is blocked by lidocaine microinjected in nucleus raphe magnus and medullary reticular formation

Cited by 147 publications

References 8 publications

Noradrenergic input to nociceptive modulatory neurons in the rat rostral ventromedial medulla

Noradrenergic input to nociceptive modulatory neurons in the rat rostral ventromedial medulla

Nociceptive flexion reflex thresholds and pain during rest and computer game play in patients with hypertension and individuals at risk for hypertension

Convergence of multiple pelvic organ inputs in the rat rostral medulla

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