Single-unit responses of serotonergic medullary and pontine raphe neurons to environmental cooling in freely moving cats

Martín-Cora, Francisco; Fornal, Casimir A.; Metzler, Christine W.; Jacobs, Barry L.

doi:10.1016/s0306-4522(00)00133-0

Cited by 45 publications

(45 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A recent report from the same authors (39) adds to their model by showing that lPBN neurons are responsive to skin cooling and that these neurons project to POA. Collectively, the current data suggest and previous neurophysiological data in intact and also in decerebrated rats show that RPa neurons themselves are activated by cold exposure (17,32,46,54), thereby suggesting a revision of that aspect of their model. We hypothesize that the potent effects of cold exposure on HR, IBAT, and heart NETO in CD rats, as well as the defense of T c by CD rats at 8 and 12°C exposures, are the result of skin afferent processing in RPa neurons (not directly measured in our studies) that drive sympathetic outflows in the absence of descending neural projections from POa or from DMH, as well as in the absence of ascending projections from lPBN to POA.…”

Section: Discussionsupporting

confidence: 70%

Energetic responses to cold temperatures in rats lacking forebrain-caudal brain stem connections

Nautiyal

Dailey

Brito

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

Hypothalamic neurons are regarded as essential for integrating thermal afferent information from skin and core and issuing commands to autonomic and behavioral effectors that maintain core temperature (T(c)) during cold exposure and for the control of energy expenditure more generally. Caudal brain stem neurons are necessary elements of the hypothalamic effector pathway and also are directly driven by skin and brain cooling. To assess whether caudal brain stem processing of thermal afferent signals is sufficient to drive endemic effectors for thermogenesis, heart rate (HR), T(c), and activity responses of chronic decerebrate (CD) and control rats adapted to 23 degrees C were compared during cold exposure (4, 8, or 12 degrees C) for 6 h. Other CDs and controls were exposed to 4 or 23 degrees C for 2 h, and tissues were processed for norepinephrine turnover (NETO), a neurochemical measure of sympathetic drive. Controls maintained T(c) for all temperatures. CDs maintained T(c) for the 8 and 12 degrees C exposures, but T(c) declined 2 degrees C during the 4 degrees C exposure. Cold exposure elevated HR in CDs and controls alike. Tachycardia magnitude correlated with decreases in environmental temperature for controls, but not CDs. Cold increased NETO in brown adipose tissue, heart, and some white adipose tissue pads in CDs and controls compared with their respective room temperature controls. These data demonstrate that, in neural isolation from the hypothalamus, cold exposure drives caudal brain stem neuronal activity and engages local effectors that trigger sympathetic energetic and cardiac responses that are comparable in many, but not in all, respects to those seen in neurologically intact rats.

show abstract

Section: Discussionsupporting

confidence: 70%

Energetic responses to cold temperatures in rats lacking forebrain-caudal brain stem connections

Nautiyal

Dailey

Brito

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

show abstract

“…There are also physiological differences between serotonergic cells located in different nuclei. For instance, cells in raphe pallidus (RP), but not in dorsal raphe, are activated when the animal is placed in a cold environment (Martin-Cora et al 2000). Therefore, data gathered from study of rostral serotonergic cells should be considered, but may not always apply, when trying to understand the function of caudal serotonergic cells.…”

Section: Serotonergic Cells In the Medullary Raphe And Ventromedial Rmentioning

confidence: 99%

“…Aghajanian and colleagues have accumulated a wealth of evidence that serotonergic cells in the rat dorsal raphe have long-duration action potentials, a slow and regular discharge pattern, and are sensitive to 5HT-1A receptor agonists (Aghajanian et al 1968, Aghajanian & Vandermaelen 1982, Vandermaelen & Aghajanian 1983, Wang & Aghajanian 1982. Subsequent investigators working in other raphe regions in the cat have then proposed, by analogy to rat serotonergic dorsal raphe neurons, that cells with long-duration action potentials and a slow and regular discharge pattern are serotonergic (Auerbach et al 1985, Fornal et al 1985, Martin-Cora et al 2000, Trulson & Jacobs 1979. Others have considered neurons whose conduction velocities are within a specified low range to be serotonergic (Chiang & Gao 1986, Wessendorf & Anderson 1983, Wessendorf et al 1981.…”

Section: Physiological Identification Of Serotonergic Cellsmentioning

confidence: 99%

Contributions of the Medullary Raphe and Ventromedial Reticular Region to Pain Modulation and Other Homeostatic Functions

Mason

2001

Annu. Rev. Neurosci.

224

154

View full text Add to dashboard Cite

The raphe magnus is part of an interrelated region of medullary raphe and ventromedial reticular nuclei that project to all areas of the spinal gray. Activation of raphe and reticular neurons evokes modulatory effects in sensory, autonomic, and motor spinal processes. Two physiological types of nonserotonergic cells are observed in the medullary raphe and are thought to modulate spinal pain processing in opposing directions. Recent evidence suggests that these cells may modulate stimulus-evoked arousal or alerting rather than pain-evoked withdrawals. Nonserotonergic cells are also likely to modulate spinal autonomic and motor circuits involved in thermoregulation and sexual function. Medullary serotonergic cells have state-dependent discharge and are likely to contribute to the modulation of pain processing, thermoregulation, and sexual function in the spinal cord. The medullary raphe and ventromedial reticular region may set sensory, autonomic, and motor spinal circuits into configurations that are appropriate to the current behavioral state.

show abstract

“…Whether the effects of exogenous 5-HT 1A receptor activation with DPAT on BAT thermogenesis and peripheral vasoconstriction are due to a decrease in the activity (via inhibitory autoreceptors) of IML projecting 5-HT neurons or to postsynaptic inhibition of other IML projecting neurons, such as glutamatergic neurons, or to some combination, remain unclear. The idea that medullary raphé 5-HT neurons modulate sympathetic outflow to thermoregulatory effector mechanisms is supported by evidence indicating that 5-HT neurons increase their firing rates in response to cooling or PGE 2 administration and that the increase is positively correlated with BAT temperature (36,47). Moreover, local application of 5-HT into the IML increases sympathetic outflow to BAT and positively modulates the excitatory effect of locally applied NMDA (34).…”

mentioning

confidence: 98%

Activation of 5-HT_1Areceptors in the paragigantocellularis lateralis decreases shivering during cooling in the conscious piglet

Hoffman

Brown²,

Sirlin³

et al. 2007

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

Activation of 5-HT(1A) receptors in the medullary raphé decreases sympathetic outflow to thermoregulatory mechanisms, including brown adipose tissue (BAT), thermogenesis, and peripheral vasoconstriction when these mechanisms are previously activated with leptin, prostaglandins, or cooling. These same mechanisms are also inhibited during rapid eye movement (REM) sleep. It is not known whether shivering is also modulated by medullary raphé neurons. We previously showed in the conscious piglet that activation of 5-HT(1A) receptors with 8-OH-DPAT (DPAT) in the paragigantocellularis lateralis (PGCL), a medullary region lateral to the midline raphé that contains 5-HT neurons, decreases heart rate, body temperature and muscle activity during non-rapid eye movement (NREM) sleep. We therefore hypothesized that activation of 5-HT(1A) receptors in the PGCL would also attenuate shivering and peripheral vasoconstriction during cooling. During REM sleep in a cool environment, shivering, carbon dioxide production, and body temperature decreased, and ear capillary blood flow and ear skin temperature increased. Shivering associated with rapid cooling was attenuated after dialysis of DPAT into the PGCL. In animals maintained in a continuously cool environment, dialysis of DPAT into the PGCL attenuated shivering and decreased body temperature, but there were no significant increases in ear capillary blood flow or ear skin temperature. We conclude that both naturally occurring REM sleep and exogenous activation of 5-HT(1A) receptors in the PGCL are associated with a suspension of shivering during cooling. Our data are consistent with the hypothesis that 5-HT neurons in the PGCL facilitate oscillating spinal motor circuits involved in shivering but are less involved in modulating sympathetically mediated thermoregulatory mechanisms.

show abstract

Single-unit responses of serotonergic medullary and pontine raphe neurons to environmental cooling in freely moving cats

Cited by 45 publications

References 46 publications

Energetic responses to cold temperatures in rats lacking forebrain-caudal brain stem connections

Energetic responses to cold temperatures in rats lacking forebrain-caudal brain stem connections

Contributions of the Medullary Raphe and Ventromedial Reticular Region to Pain Modulation and Other Homeostatic Functions

Activation of 5-HT_1Areceptors in the paragigantocellularis lateralis decreases shivering during cooling in the conscious piglet

Contact Info

Product

Resources

About

Single-unit responses of serotonergic medullary and pontine raphe neurons to environmental cooling in freely moving cats

Cited by 45 publications

References 46 publications

Energetic responses to cold temperatures in rats lacking forebrain-caudal brain stem connections

Energetic responses to cold temperatures in rats lacking forebrain-caudal brain stem connections

Contributions of the Medullary Raphe and Ventromedial Reticular Region to Pain Modulation and Other Homeostatic Functions

Activation of 5-HT1Areceptors in the paragigantocellularis lateralis decreases shivering during cooling in the conscious piglet

Contact Info

Product

Resources

About

Activation of 5-HT_1Areceptors in the paragigantocellularis lateralis decreases shivering during cooling in the conscious piglet