The action of the A1 noradrenergic region on the activity of subfornical organ neurons in the rat

Tanaka, Junichi; Mashiko, Norifumi; Kawakami, Ayako; Hatakenaka, Satoko; Fujisawa, Shigeko; Nomura, Masahiko

doi:10.1016/s0304-3940(02)00913-8

Cited by 8 publications

(5 citation statements)

References 16 publications

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“…A1 Cells receive projections from arterial baroreceptors as well as from vagal cardiopulmonary volume receptors (Day & Sibbald, 1990; Day et al 1992). A1 Cells also project to several hypothalamic nuclei involved in water and salt homeostasis, including the subfornical organ (SFO), the median preoptic nucleus (MePO), and the magnocellular neurosecretory neurones in the paraventricular (PVN) and supraoptic nucleus (SON; Tucker et al 1987; Tanaka et al 2002). Brainstem noradrenergic neurones are activated during several conditions that affect volume and composition of the extracellular compartment (Hochstenbach & Ciriello, 1995; Howe et al 2004; Godino et al 2005).…”

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confidence: 99%

Role of catecholaminergic neurones of the caudal ventrolateral medulla in cardiovascular responses induced by acute changes in circulating volume in rats

Pedrino

Maurino

Colombari

et al. 2006

Experimental Physiology

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Several findings suggest that catecholaminergic neurones in the caudal ventrolateral medulla (CVLM) contribute to body fluid homeostasis and cardiovascular regulation. The present study sought to determine the effects of lesions of these neurones on the cardiovascular responses induced by changes in circulating volume. All experiments were performed in male Wistar rats (320-360 g). Medullary catecholaminergic neurones were lesioned by microinjection of antidopamine β-hydroxylase-saporin (6.3 ng in 60 nl; SAP rats, n = 14) into the CVLM, whereas sham rats received microinjections of free saporin (1.3 ng in 60 nl, n = 15). Two weeks later, rats were anaesthetized (urethane, 1.2 g kg −1 , I.V.), instrumented for measurement of mean arterial pressure (MAP), renal blood flow (RBF) and renal vascular conductance (RVC), and infused with hypertonic saline (HS; 3 M NaCl, 0.18 ml (100 g body weight)−1 , I.V.) or an isotonic solution (volume expansion, VE; 4% Ficoll, 1% of body weight, I.V.). In sham rats, HS induced sustained increases in RBF and RVC (155 ± 7 and 145 ± 6% of baseline, at 20 min after HS). In SAP rats, RBF responses to HS were blunted (125 ± 6%) and RVC increases were abolished (108 ± 5%) 20 min after HS. Isotonic solution increased RBF and RVC in sham rats (149 ± 10 and 145 ± 12% of baseline, respectively, at 20 min). These responses were reduced in SAP rats (131 ± 6 and 126 ± 5%, respectively, at 20 min). Pressor responses to HS were larger in SAP rats than in sham rats (17 ± 5 versus 9 ± 2 mmHg, at 20 min), whereas during VE these responses were similar in both groups (6 ± 3 versus 4 ± 6 mmHg, at 20 min). Immunohistochemical analysis indicates that microinjections of anti-DβH-saporin produced extensive destruction within the A1/C1 cell groups in the CVLM. These results suggest that catecholaminergic neurones mediate the cardiovascular responses to VE or increases in plasma sodium levels.

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confidence: 99%

Role of catecholaminergic neurones of the caudal ventrolateral medulla in cardiovascular responses induced by acute changes in circulating volume in rats

Pedrino

Maurino

Colombari

et al. 2006

Experimental Physiology

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“…The results of Tanaka et al (27) from electrical stimulation of rat A1 area also suggest that adrenergic neuronal inputs to the SFO are mediated partly through ␤-adrenoceptors. The action through ␤-adrenoceptors was inhibitory.…”

Section: Discussionmentioning

confidence: 86%

“…Tanaka et al (27) demonstrated from electrical stimulation of the A1 area in the rat that adrenergic excitatory neuronal inputs to the SFO are mediated mainly through ␣-adrenoceptors (27) and suggested that the pathways may transmit information from peripheral baroreceptors (25). The results of microdialysis experiments suggest that the NA level in the region of the SFO changes with blood pressure (26).…”

Section: Discussionmentioning

confidence: 99%

Activation of subfornical organ neurons in rats through pre- and postsynaptic α-adrenoceptors

Honda

Ono²,

Kataoka³

et al. 2006

American Journal of Physiology-Regulatory, Integrative and Comp

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(NA) and its analogs on subfornical organ (SFO) neurons in rat slice preparations were investigated by using whole cell patch-clamp recording. In the current-clamp mode, the application of NA at 10 -100 M produced membrane depolarization (63%, 17 responsive neurons/27 neurons tested) and hyperpolarization (22%, 6/27 neurons). In the voltage-clamp mode, NA application at 1-100 M produced inward currents (69%, 42/61 neurons) and outward currents (23%, 14/61 neurons). These currents remained in the presence of TTX or both glutamate and GABA receptor antagonists. In most of the neurons (25/31 neurons) showing inward currents in the presence of NA, the membrane conductance was not changed by voltage ramps or hyperpolarizing pulse stimulation. Similar responses were obtained by the application of the ␣ 1-agonist phenylephrine. The phenylephrineinduced inward currents were inhibited by the ␣1-antagonist prazosin. The ␣ 2-agonist clonidine decreased the frequency of spontaneous GABAergic inhibitory postsynaptic currents (4/10 neurons). In addition, RT-PCR assay and immunohistochemical staining showed the existence of ␣ 1-adrenoceptors in the SFO. The results suggest that SFO neurons in rats are activated postsynaptically through ␣ 1-adrenoceptors and that the activation is enhanced by suppressing GABAergic inhibitory synaptic inputs through presynaptic ␣ 2-adrenoceptors. patch clamp; slice preparation; noradrenaline THE SUBFORNICAL ORGAN (SFO), which juts ventrally from the hippocampal commissura into the third cerebral ventricle, is a circumventricular organ. The SFO receives various neural inputs from brain regions, whereas it lacks a blood-brain barrier and has an abundant vascular supply (for a review, see Ref. 14). From these properties, the SFO has been thought to possess various sensors for neurotransmitters and blood-and cerebrospinal fluid-borne substances, and subsequently to control body fluid balance and the cardiovascular system (for reviews, see Refs. 8 and 15). In fact, angiotensinergic, cholinergic, and hypertonic activation of SFO neurons elicits water intake (23) and vascular responses, and increases vasopressin release from the posterior pituitary (11,12). Noradrenaline (NA), which is released from catecholaminergic fibers and the adrenal medulla, may be one of such bioactive substances affecting SFO neurons. The catecholaminergic neurons in the A1 and A2 areas of the medulla project directly to various brain regions, including the SFO (3, 10). The NA level in the region of the SFO is increased by hemorrhage, whereas it is decreased by an elevation in arterial pressure (26). The peripheral baroreceptor information may be transmitted from the nucleus of the solitary tract to the SFO through ␣-adrenoceptors (16, 25). Further, microinjection of NA into the SFO increases water intake (17). Thus NA at the level of the SFO may play an important role in the regulation of cardiovascular function and body fluid homeostasis. However, little is known about whether the SFO neurons themselves are directly affec...

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“…Both the A1 and the A2 neurons innervate the forebrain through the ventral noradrenergic bundle, but the extent in the overlap in the innervation targets of these two groups has not been fully determined (Rinaman, 2011). The A1 and A2 neurons both project to hypothalamic areas, including various subdivisions of the paraventricular nucleus and the supraoptic nucleus (Sawchenko and Swanson, 1981, Raby and Renaud, 1989, Kvetnansky et al, 2009), the amygdala, particularly the central nucleus of the amygdala (Jia et al, 1992, Roder and Ciriello, 1993), and the subfornical organ (Tanaka et al, 2002). Although these two nuclei share projection target areas, it has been reported that A1 and A2 noradrenergic neurons innervate distinct subdivisions or type of neurons (Sawchenko and Swanson, 1981).…”

Section: Discussionmentioning

confidence: 99%

Distribution of catecholaminergic presympathetic-premotor neurons in the rat lower brainstem

Nam

Kerman

2016

Neuroscience

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We previously characterized the organization of presympathetic-premotor neurons (PSPMNs), which send descending poly-synaptic projections with collaterals to skeletal muscle and the adrenal gland. Such neurons may play a role in shaping integrated adaptive responses, and many of them were found within well-characterized regions of noradrenergic cell populations suggesting that some of the PSPMNs are catecholaminergic. To address this issue, we used retrograde trans-synaptic tract-tracing with attenuated pseudorabies virus (PRV) recombinants combined with multi-label immunofluorescence to identify PSPMNs expressing tyrosine hydroxylase (TH). Our findings indicate that TH-immunoreactive (ir) PSPMNs are present throughout the brainstem within multiple cell populations, including the A1, C1, C2, C3, A5 and A7 cell groups along with the locus coeruleus (LC) and the nucleus subcoeruleus (SubC). The largest numbers of TH-ir PSPMNs were located within the LC and SubC. Within SubC and the A7 cell group, about 70% of TH-ir neurons were PSPMNs, which was a significantly greater fraction of neurons than in the other brain regions we examined. These findings indicate that TH-ir neurons near the pontomesencephalic junction that are distributed across the LC, SubC, and the A7 may play a prominent role in somatomotor-sympathetic integration, and that the major functional role of the A7 and SubC noradrenergic cell groups maybe in the coordination of concomitant activation of somatomotor and sympathetic outflows. These neurons may participate in mediating homeostatic adaptations that require simultaneous activation of sympathetic and somatomotor nerves in the periphery.

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The action of the A1 noradrenergic region on the activity of subfornical organ neurons in the rat

Cited by 8 publications

References 16 publications

Role of catecholaminergic neurones of the caudal ventrolateral medulla in cardiovascular responses induced by acute changes in circulating volume in rats

Role of catecholaminergic neurones of the caudal ventrolateral medulla in cardiovascular responses induced by acute changes in circulating volume in rats

Activation of subfornical organ neurons in rats through pre- and postsynaptic α-adrenoceptors

Distribution of catecholaminergic presympathetic-premotor neurons in the rat lower brainstem

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