Differential projections from gustatory responsive regions of the parabrachial nucleus to the medulla and forebrain

Karimnamazi, Hamid; Travers, Joseph B.

doi:10.1016/s0006-8993(98)00951-2

Cited by 122 publications

(97 citation statements)

References 61 publications

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“…Other inputs may involve interneurons within the NST, projections from the opposite NST (Whitehead et al 2000), or descending connections from the LH through the PbN (Hosoya and Matsushita 1981), which in turn sends some descending axons to the NST (Bianchi et al 1998;Karimnamazi and Travers 1998). Indeed, we have recently observed a few cells that exhibit orthodromic impulses in the hamster NST following ipsilateral PbN stimulation (Cho et al 2002).…”

Section: Connections Between the Lh And The Rostral Nstmentioning

confidence: 95%

Taste Responses of Neurons of the Hamster Solitary Nucleus Are Enhanced by Lateral Hypothalamic Stimulation

Cho

Smith

2002

Journal of Neurophysiology

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. Taste responses of neurons of the hamster solitary nucleus are enhanced by lateral hypothalamic stimulation. J Neurophysiol 87: 1981-1992, 2002; 10.1152/jn.00765.2001. Gustatory responses in the brain stem are modifiable by several physiological factors, including blood insulin and glucose, intraduodenal lipids, gastric distension, and learning, although the neural substrates for these modulatory effects are not known. Stimulation of the lateral hypothalamus (LH) produces increases in food intake and alterations in taste preference behavior, whereas damage to this area has opposite effects. In the present study, we investigated the effects of LH stimulation on the neural activity of taste-responsive cells in the nucleus of the solitary tract (NST) of the hamster. Bipolar stimulating electrodes were bilaterally implanted in the LH, and the responses of 99 neurons in the NST, which were first characterized for their taste sensitivities, were tested for their response to both ipsilateral and contralateral LH stimulation. Half of the tasteresponsive cells in the NST (49/99) were modulated by LH stimulation. Contralateral stimulation was more often effective (41 cells) than ipsilateral (13 cells) and always excitatory; 10 cells were excited bilaterally. Six cells were inhibited by ipsilateral stimulation. A subset of these cells (n ϭ 13) was examined for the effects of microinjection of DL-homocysteic acid (DLH), a glutamate receptor agonist, into the LH. The effects of electrical stimulation were completely mimicked by DLH, indicating that cell somata in and around the LH are responsible for these effects. Other cells (n ϭ 14) were tested for the effects of electrical stimulation of the LH on the responses to stimulation of the tongue with 0.032 M sucrose, NaCl, and quinine hydrochloride, and 0.0032 M citric acid. Responses to taste stimuli were more than doubled by the excitatory influence of the LH. These data show that the LH, in addition to its role in feeding and metabolism, exerts descending control over the processing of gustatory information through the brain stem.

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Section: Connections Between the Lh And The Rostral Nstmentioning

confidence: 95%

Taste Responses of Neurons of the Hamster Solitary Nucleus Are Enhanced by Lateral Hypothalamic Stimulation

Cho

Smith

2002

Journal of Neurophysiology

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“…input from brain stem orosensory and viscerosensory nuclei, including the rostral (gustatory) nucleus of the solitary tract (rNST), caudal (visceral) NST (cNST), the parabrachial nucleus, and ventrolateral medulla (8,28,31,54,64). Results from decerebrate preparations in which visceral signals, such as gastric load (49) and glucoprivation (15,21), modify the amount of a palatable (sweet) stimulus that is consumed, suggest that these local pathways exert a potent influence over this consummatory circuitry (reviewed in Refs.…”

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confidence: 99%

Activation of NPY receptors suppresses excitatory synaptic transmission in a taste-feeding network in the lower brain stem

Chen

Travers

2012

American Journal of Physiology-Regulatory, Integrative and Comp

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Chen Z, Travers SP, Travers JB. Activation of NPY receptors suppresses excitatory synaptic transmission in a taste-feeding network in the lower brain stem. Am J Physiol Regul Integr Comp Physiol 302: R1401-R1410, 2012. First published April 18, 2012 doi:10.1152/ajpregu.00536.2011.-Consummatory responses to taste stimuli are modulated by visceral signals processed in the caudal nucleus of the solitary tract (cNST) and ventrolateral medulla. On the basis of decerebrate preparations, this modulation can occur through local brain stem pathways. Among the large number of neuropeptides and neuromodulators implicated in these visceral pathways is neuropeptide Y (NPY), which is oftentimes colocalized in catecholaminergic neurons themselves implicated in glucoprivic-induced feeding and satiety. In addition to the cNST and ventrolateral medulla, noradrenergic and NPY receptors are found in circumscribed regions of the medullary reticular formation rich in preoromotor neurons. To test the hypothesis that NPY may act as a neuromodulator on preoromotor neurons, we recorded the effects of bath application of NPY and specific Y1 and Y2 agonists on currents elicited from electrical stimulation of the rostral (taste) NST in prehypoglossal neurons in a brain stem slice preparation. A high proportion of NST-driven responses were suppressed by NPY, as well as Y1 and Y2 agonists. On the basis of paired pulse ratios and changes in membrane resistance, we concluded that Y1 receptors influence these neurons both presynaptically and postsynaptically and that Y2 receptors have a presynaptic locus. To test the hypothesis that NPY may act in concert with norepinephrine (NE), we examined neurons showing suppressed responses in the presence of a Y2 agonist and demonstrated a greater degree of suppression to a Y2 agonist/NE cocktail. These suppressive effects on preoromotoneurons may reflect a satiety pathway originating from A2 neurons in the caudal brain stem.oromotor; ingestion; reticular formation; norepinephrine CIRCUITS CONTROLLING THE CONSUMMATORY behaviors of ingestion are located in the lower brain stem (7,38,40,56). These circuits extend from the pons to the spinal medullary junction to encompass both sensory and motor nuclei, as well as specific regions of the reticular formation (RF). One region, immediately subjacent to the nucleus of the solitary tract (NST), which includes both the intermediate subdivision of the medullary RF (IRt) and the more lateral parvocellular RF (PCRt), contains a dense constellation of preoromotor neurons (29, 37, 58) that provide a potent source of excitatory drive to the oromotor nuclei (59, 60). Functional inactivation of the IRt/PCRt with either the GABA agonist muscimol or glutamatergic antagonists suppresses consummatory behavior in the awake freely moving rat (10,11,57).An additional, integrative role for the IRt/PCRt is suggested by input from forebrain sites involved in homeostatic, regulatory, and motor function (9, 43, 50, 61), as well as overlapping input from brain stem orosensory and vis...

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“…central gustatory pathway; pons; electrophysiology THE PARABRACHIAL NUCLEI (PbN) and the parvicellular part of the ventroposteromedial nucleus of the thalamus (VPMpc) are the second and tertiary central relays for taste information processing in rodents, respectively (4,13,17,28,45,49,51). Gustatory information elicited from the tongue and oropharyngeal cavity is initially carried to the rostral portion of the nucleus of the solitary tract (NST) by the VIIth, IXth, and Xth cranial nerves, and these terminals are distributed in a topographic fashion with rostral-caudal sequence in the rostral NST (2,9,23,24,89).…”

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confidence: 99%

Modulation of activity of gustatory neurons in the hamster parabrachial nuclei by electrical stimulation of the ventroposteromedial nucleus of the thalamus

Mao¹,

Cho²,

Li³

2008

American Journal of Physiology-Regulatory, Integrative and Comp

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(VPMpc) is positioned at the key site between the gustatory parabrachial nuclei (PbN) and the gustatory cortex for relaying and processing gustatory information via the thalamocortical pathway. Although neuroanatomical and electrophysiological studies have provided information regarding the gustatory projection from PbN to VPMpc, the exact relationship between PbN and VPMpc, especially the efferent projection involving VPMpc to PbN, is obscure. Here we investigated the reciprocal connection between these two gustatory relays in urethaneanesthetized hamsters. We recorded from 114 taste-responsive neurons in the PbN and examined their responsiveness to electrical stimulation of the VPMpc bilaterally. Stimulation of either or both of the ipsilateral or contralateral VPMpc antidromically activated 109 gustatory PbN neurons. Seventy-two PbN neurons were antidromically activated after stimulation of both sides of the VPMpc, indicating that taste neurons in the PbN project heavily to the bilateral VPMpc. Stimulation of VPMpc also orthodromically activated 110 of PbN neurons, including 106 VPMpc projection neurons. Seventyeight neurons were orthodromically activated bilaterally. Among orthodromic activations of the PbN cells, the inhibitory response was the dominant response; 106 cells were inhibited, including 10 neurons that were also excited contralaterally, indicating that taste neurons in the PbN are subject to strong inhibitory control from VPMpc. Moreover, stimulation of VPMpc altered taste responses of the neurons in the PbN, indicating that VPMpc modulates taste responses of PbN neurons. These results may provide functional insight of neural circuitry for taste processing and modulation involving these two nuclei.central gustatory pathway; pons; electrophysiology THE PARABRACHIAL NUCLEI (PbN) and the parvicellular part of the ventroposteromedial nucleus of the thalamus (VPMpc) are the second and tertiary central relays for taste information processing in rodents, respectively (4,13,17,28,45,49,51). Gustatory information elicited from the tongue and oropharyngeal cavity is initially carried to the rostral portion of the nucleus of the solitary tract (NST) by the VIIth, IXth, and Xth cranial nerves, and these terminals are distributed in a topographic fashion with rostral-caudal sequence in the rostral NST (2,9,23,24,89). From the NST, ascending gustatory fibers project to third-order taste cells within the PbN of the pons (7,22,42,46,(53)(54)(55)87). Two separate routes carry taste information from the PbN further to the forebrain taste areas and cortex: the ventral forebrain pathway that involves the central nucleus of the amygdala (CeA), the lateral hypothalamus (LH), the bed nucleus of the stria terminalis (BNST), the substantia innominata (3,12,16,21,31,33,34,41,47,63,64,71); and the thalamocortical pathway that is characterized by the involvement of the bilateral VPMpc, which, in turn, carries taste information to the gustatory cortex (GC) (5,25,45,48,51).The PbN is a critical neural substrate for a number...

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Differential projections from gustatory responsive regions of the parabrachial nucleus to the medulla and forebrain

Cited by 122 publications

References 61 publications

Taste Responses of Neurons of the Hamster Solitary Nucleus Are Enhanced by Lateral Hypothalamic Stimulation

Taste Responses of Neurons of the Hamster Solitary Nucleus Are Enhanced by Lateral Hypothalamic Stimulation

Activation of NPY receptors suppresses excitatory synaptic transmission in a taste-feeding network in the lower brain stem

Modulation of activity of gustatory neurons in the hamster parabrachial nuclei by electrical stimulation of the ventroposteromedial nucleus of the thalamus

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