Potassium Permanganate Can Mark the Site of Microdialysis in Brain Sections

Sun, Man-Hua; Hildebrandt, Laurie; Curran, Aidan K.; Darnall, Robert A.; Chen, Gengxin; Filiano, James J.

doi:10.1179/014788800794813110

Cited by 12 publications

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“…For microdialysis studies, a microdialysis probe (BAS, West Lafayette, IN, USA) with a dialysis membrane at the tip, which was 1 mm long × 0.32 mm in diameter, was placed (within 1–1.5 m m from the ventral medullary surface) in the left side of the brainstem using stereotaxic co‐ordinates developed previously (Sun et al 2000).…”

Section: Methodsmentioning

confidence: 99%

“…Upon termination of the experiment, the dialysis probe was removed and replaced by a dialysis probe with the tip broken back slightly. We injected 20–50 μl of filtered 1% aqueous potassium permanganate solution through the broken dialysis probe to mark the site of dialysis (Sun et al 2000). The brainstem was removed and the ventral surface photographed.…”

Section: Methodsmentioning

confidence: 99%

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Baroreceptor‐mediated inhibition of respiration after peripheral and central administration of a 5‐HT_1A receptor agonist in neonatal piglets

Curran¹,

Leiter²

2007

Experimental Physiology

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Inhibition of neurones in the ventral medulla accentuates the respiratory inhibition associated with acute blood pressure elevation in piglets. Activation of presynaptic 5-HT 1A receptors inhibits serotonergic neurones in the ventral medulla and caudal raphé, and we tested the hypothesis that administration of 8-hydroxydipropylaminotetralin (8-OH-DPAT), a 5-HT 1A agonist, within the rostroventral medulla and caudal raphé would enhance baroreceptor-mediated inhibition of respiratory activity in decerebrate, neonatal piglets. Baroreceptor stimulation was achieved by inflating a balloon in the distal aorta to elevate carotid blood pressure. After two to four control trials of baroreceptor stimulation, each piglet was given either a single intravenous (I.V.) dose of 10 μg kg -1 8-OH-DPAT or treated by adding 10 or 30 mM 8-OH-DPAT to the dialysate for ∼10 min to inhibit serotonergic neurones, after which the baroreceptor stimulation trials were repeated. Baroreceptor stimulation reduced respiratory activity, particularly the respiratory frequency, which diminished from 35.7 ± 3.3 to 33.8 ± 3.1 breaths min -1 (P < 0.02) and, following I.V. 8-OH-DPAT, baroreceptor-mediated inhibition of respiratory output was significantly accentuated (P < 0.05); the respiratory frequency declined from 34.5 ± 3.6 to 26.5 ± 2.9 breaths min -1 . Increasing aortic blood pressure reduced the respiratory frequency (P < 0.01), but focal dialysis of 10 or 30 mM 8-OH-DPAT had, on average, no effect on the ventilatory inhibition associated with an acute elevation of blood pressure. We conclude that activation of 5-HT 1A receptors after systemic administration of 8-OH-DPAT enhanced baroreflex-mediated inhibition of ventilation, but this effect cannot be attributed to 5-HT 1A receptor activation within the rostroventral medulla and caudal raphé.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Baroreceptor‐mediated inhibition of respiration after peripheral and central administration of a 5‐HT_1A receptor agonist in neonatal piglets

Curran¹,

Leiter²

2007

Experimental Physiology

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“…At the conclusion of experiments, microinjections of 20 -50 l of 1% potassium permanganate were made through a broken microdialysis probe to mark the location of the tip of each microdialysis probe (85). Each piglet was killed with a lethal intraarterial injection of pentobarbital sodium followed by an intracardiac injection of 5-10 ml of saturated potassium chloride.…”

Section: Methodsmentioning

confidence: 99%

Activation of 5-HT_1Areceptors in medullary raphé disrupts sleep and decreases shivering during cooling in the conscious piglet

Brown¹,

Sirlin²,

Benoit³

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

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Activation of 5-HT 1A receptors in the medullary raphé decreases sympathetically mediated brown adipose tissue (BAT) thermogenesis and peripheral vasoconstriction when previously activated with leptin, LPS, prostaglandins, or cooling. It is not known whether shivering is also modulated by medullary raphé 5-HT 1A receptors. We previously showed in conscious piglets that activation of 5-HT 1A receptors with (Ϯ)-8-hydroxy-2-(dipropylamino)-tetralin (8-OH-DPAT) in the paragigantocellularis lateralis (PGCL), a medullary region lateral to the raphé that contains substantial numbers of 5-HT neurons, eliminates rapid eye movement (REM) sleep and decreases shivering in a cold environment, but does not attenuate peripheral vasoconstriction. Hoffman JM, Brown JW, Sirlin EA, Benoit AM, Gill WH, Harris MB, Darnall RA. Am J Physiol Regul Integr Comp Physiol 293: R518 -R527, 2007. We hypothesized that, during cooling, activation of 5-HT 1A receptors in the medullary raphé would also eliminate REM sleep and, in contrast to activation of 5-HT 1A receptors in the PGCL, would attenuate both shivering and peripheral vasoconstriction. In a continuously cool environment, dialysis of 8-OH-DPAT into the medullary raphé resulted in alternating brief periods of non-REM sleep and wakefulness and eliminated REM sleep, as observed when 8-OH-DPAT is dialyzed into the PGCL. Moreover, both shivering and peripheral vasoconstriction were significantly attenuated after 8-OH-DPAT dialysis into the medullary raphé. The effects of 8-OH-DPAT were prevented after dialysis of the selective 5-HT 1A receptor antagonist WAY-100635. We conclude that, during cooling, exogenous activation of 5-HT 1A receptors in the medullary raphé decreases both shivering and peripheral vasoconstriction. Our data are consistent with the hypothesis that neurons expressing 5-HT 1A receptors in the medullary raphé facilitate spinal motor circuits involved in shivering, as well as sympathetic stimulation of other thermoregulatory effector mechanisms. thermoregulation; serotonin; brain stem; raphé; the sudden infant death syndrome MANY NEURONS IN THE MEDULLARY raphé, including serotonergic (5-HT) neurons, project to the intermediolateral cell column (IML) of the spinal cord and modulate sympathetic outflow to thermoregulatory effector mechanisms, including brown adipose tissue (BAT) thermogenesis, vasoconstriction of thermoregulatory cutaneous vascular beds, and heart rate (HR) (14,53,58,86,89). Studies in anesthetized and conscious animals have shown that activation of 5-HT 1A receptors in the medullary raphé with the selective agonist, (Ϯ)-8-hydroxy-2-(dipropylamino)-tetralin (8-OH-DPAT), attenuates sympathetic outflow to BAT and peripheral vessels when previously elevated by LPS, leptin, or cooling (11,52,59,63,64).There is mounting evidence that medullary raphé 5-HT neurons modulate sympathetically mediated thermoregulatory mechanisms; however, little is known about the role of medullary raphé 5-HT neurons in shivering thermogenesis. Shivering is an involuntary tremor that i...

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“…Briefly, under sterile conditions and using isofluorane anesthesia, a dual-lumen catheter was placed through the femoral artery into the abdominal aorta, and a telemetric thermistor was placed subcutaneously just lateral to the abdominal midline. After placement in a stereotaxic apparatus, a microdialysis guide tube was placed through a burr hole in the skull using coordinates derived from a regression formula (Sun et al, 2000). An attempt was made to place the tip between the midline and the medial border of the facial nucleus near the ventral surface.…”

Section: Methodsmentioning

confidence: 99%

“…At the conclusion of experiments, each piglet was killed with an injection of sodium pentobarbital followed by an intracardiac injection of 5-10 ml of saturated potassium chloride. Microinjections of 20 -50 l of 1% potassium permanganate were made through a broken microdialysis probe to mark the location of the tip of the microdialysis probe in reference to external landmarks (Sun et al, 2000). The brainstem was removed and frozen in cryoembedding medium (Tissue-Tek OCT; Sakura Finetek, Torrance, CA).…”

Section: -Oh-dpat Dosesmentioning

confidence: 99%

Inhibition of Serotonergic Neurons in the Nucleus Paragigantocellularis Lateralis Fragments Sleep and Decreases Rapid Eye Movement Sleep in the Piglet: Implications for Sudden Infant Death Syndrome

Darnall¹,

Harris²,

Gill³

et al. 2005

J. Neurosci.

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Serotonergic receptor binding is altered in the medullary serotonergic nuclei, including the paragigantocellularis lateralis (PGCL), in many infants who die of sudden infant death syndrome (SIDS). The PGCL receives inputs from many sites in the caudal brainstem and projects to the spinal cord and to more rostral areas important for arousal and vigilance. We have shown previously that local unilateral nonspecific neuronal inhibition in this region with GABA A agonists disrupts sleep architecture. We hypothesized that specifically inhibiting serotonergic activity in the PGCL would result in less sleep and heightened vigilance. We analyzed sleep before and after unilaterally dialyzing the 5-HT 1A agonist (

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Potassium Permanganate Can Mark the Site of Microdialysis in Brain Sections

Cited by 12 publications

References 0 publications

Baroreceptor‐mediated inhibition of respiration after peripheral and central administration of a 5‐HT_1A receptor agonist in neonatal piglets

Baroreceptor‐mediated inhibition of respiration after peripheral and central administration of a 5‐HT_1A receptor agonist in neonatal piglets

Activation of 5-HT_1Areceptors in medullary raphé disrupts sleep and decreases shivering during cooling in the conscious piglet

Inhibition of Serotonergic Neurons in the Nucleus Paragigantocellularis Lateralis Fragments Sleep and Decreases Rapid Eye Movement Sleep in the Piglet: Implications for Sudden Infant Death Syndrome

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Potassium Permanganate Can Mark the Site of Microdialysis in Brain Sections

Cited by 12 publications

References 0 publications

Baroreceptor‐mediated inhibition of respiration after peripheral and central administration of a 5‐HT1A receptor agonist in neonatal piglets

Baroreceptor‐mediated inhibition of respiration after peripheral and central administration of a 5‐HT1A receptor agonist in neonatal piglets

Activation of 5-HT1Areceptors in medullary raphé disrupts sleep and decreases shivering during cooling in the conscious piglet

Inhibition of Serotonergic Neurons in the Nucleus Paragigantocellularis Lateralis Fragments Sleep and Decreases Rapid Eye Movement Sleep in the Piglet: Implications for Sudden Infant Death Syndrome

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Baroreceptor‐mediated inhibition of respiration after peripheral and central administration of a 5‐HT_1A receptor agonist in neonatal piglets

Baroreceptor‐mediated inhibition of respiration after peripheral and central administration of a 5‐HT_1A receptor agonist in neonatal piglets

Activation of 5-HT_1Areceptors in medullary raphé disrupts sleep and decreases shivering during cooling in the conscious piglet