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Taste and Food Choice
Published in Alan R. Hirsch, Nutrition and Sensation, 2023
To control somatic reflexes, clusters of cells in the ventral regions of gustatory NST send projections to the retrofacial area, trigeminal motor nucleus, nucleus ambiguus, and hypoglossal nucleus. The contrary behavioral reactions of acceptance and rejection may be driven by anatomically distinct taste inputs (Grill and Norgren 1978). The greater superficial petrosal and chorda tympani nerves are most sensitive to sweet and salty stimuli and could activate circuits that evoke acceptance responses. The glossopharyngeal nerve is responsive to sour and bitter qualities and could stimulate a separate population of NST taste cells from which rejection reflexes were organized.
Treatment of Chronic Fatigue Syndrome
Published in Jay A. Goldstein, Chronic Fatigue Syndromes, 2020
Consideration of the regulation of the motor function of the trigeminal nerve, which innervates the muscles of mastication, yields insights into the possible pathophysiology of bruxism and TMPDS. Several papers over the last decade from the laboratory of M. Ohta in Kyushu, Japan,136 and Gary Bobo137 in Paris implicate the central amygdaloid nucleus in control of masseteric and myohyoid digastric function. The amygdaloid complex projects fibers to the brain stem, around the trigeminal motor nucleus, primarily on the ipsilateral side. It appears from Ohta’s work that amygdaloid stimulation can excite neurons in the supratrigeminal area (STA) which projects to the contralateral trigeminal motor nucleus. Ohta concludes that “the shortest crossing amygdala-motoneuronal pathway is probably disynaptic and mediated by commisural STA neurons.”
Brainstem Mechanisms of Gustation
Published in Robert H. Cagan, Neural Mechanisms in Taste, 2020
David V. Smith, Takayuki Marui
All of these behavioral influences appear to be intact in both decerebrate and normal animals, suggesting that taste can exert its role through local circuits within the brainstem. The orofacial and other motor responses to gustatory stimulation seen in normal rats124 are present in chronic decerebrate rats,131 as is salivation in decerebrate rabbits.129 Thus, these basic ingestive responses appear to depend upon a neural substrate complete within the brainstem. The organization of this neural substrate is not simple, involving primarily a polysynaptic pathway between sensory input and motor output.132 Most afferent projections to the motor nuclei controlling orofacial responses, for example, come from the brainstem reticular formation, usually from areas adjacent to other motor nuclei.132 Like the afferent terminations of the Vllth, IXth, and Xth nerves within the NTS, the projections to the oral motor nuclei are organized along the rostrocaudal axis. Most cells projecting to the trigeminal motor nucleus are rostral within the reticular formation to those projecting to the hypoglossal and ambiguus nuclei, which are rostral to those sending fibers to the facial nucleus.132 There are very few direct projections to these motor nuclei from cells within the gustatory centers in the NTS or within the sensory trigeminal nuclei. Greater comprehension of the functional organization of taste within the brainstem is contingent on understanding this complex circuitry.
Overexpression of NaV1.6 in the rostral ventrolateral medulla in rats mediates stress-induced hypertension via glutamate regulation
Published in Clinical and Experimental Hypertension, 2022
Lei Tong, Mengyu Xing, Jiaxiang Wu, Shuai Zhang, Dechang Chu, Haili Zhang, Fuxue Chen, Dongshu Du
Voltage-gated sodium channels (VGSCs) are one of the key regulators that control the excitability of neurons because they are indispensable for the propagation and initiation of action potentials. VGSCs are important proteins of the cell membrane and consist of an α-subunit and four auxiliary β-subunits. The α-subunit is the principal structural component that shapes the ion-conducting pore and is responsible for activation and inactivation of the channel gate. The four auxiliary β-subunits help the α-subunit to modulate the gating kinetics. In mammals, the Nax family consists of 10 α-subunit genes that encode NaV1.1 to NaV1.9 and Nax. NaV1.6 is a vital VGSC subtype that mediates continuous Na+ currents in the cell. NaV1.6 is expressed in the brain, including the medulla oblongata (8,9), trigeminal motor nucleus, facial nucleus, dorsal motor nucleus of the vagus, hypoglossal nucleus, and other autonomic areas (10). Our previous study found that expression of the VGSC NaV1.6 in the rat RVLM gradually increased with stress and reached the highest level on the tenth day of stress induction. When NaV1.6 expression was knocked down, the blood pressure returned to the normal range (6). Resurgent Na+ currents contribute to the generation and transmission of neurotransmitters, such as glutamic acid, and high frequency firing. NaV1.6 facilitates an increase in neuronal hyperexcitability during the development of epileptogenesis, and studies have shown that elevated NaV1.6 expression causes excessive excitation of neurons (11).
Treatment with the essential amino acid L-tryptophan reduces masticatory impairments in experimental cerebral palsy
Published in Nutritional Neuroscience, 2021
Diego Cabral Lacerda, Raul Manhães-de-Castro, Henrique José Cavalcanti Bezerra Gouveia, Yves Tourneur, Barbara Juacy Costa de Santana, Renata Emmanuele Assunção Santos, Jacques Olivier-Coq, Kelli Nogueira Ferraz-Pereira, Ana Elisa Toscano
Rhythmical oral motor activity such as sucking and chewing is under the control of a network of brainstem neurons [11]. The regulation of these activities occurs in the brainstem, particularly in the central pattern generators (CPGs)[12,13]. Sucking and chewing CPGs extend from the rostral poles of the trigeminal motor nucleus (TMN) to the rostral pole of the facial nucleus[12]. In addition, the maturation of sucking and chewing involves neurotransmitter systems, including serotonin (5-HT)[14]. Several studies demonstrate that the serotonergic system is crucial to control TMN activities[14–16]. The TMN receives a dense serotonergic input and contains serotonergic receptors[14], which facilitate the discharges of trigeminal motoneurons. Moreover, 5-HT is involved in the morphogenesis of the craniofacial, dental, bone and muscle structures of the stomatognathic system [17,18], and all 5-HT receptor subtypes are expressed in the developing craniofacial structures as well [18]. Thus, an intact serotonergic system is necessary for the maturation of the neural structures involved in sucking and chewing.
Targets for obstructive sleep apnea pharmacotherapy: principles, approaches, and emerging strategies
Published in Expert Opinion on Therapeutic Targets, 2023
Importantly, the airway collapsing and closing forces are opposed by the pressure generated by pharyngeal muscle activation (PMUSCLE, Figure 1). Pharyngeal muscle tone is expressed as tonic activity (i.e. the prevailing continuous or background tone) and phasic activity (i.e. respiratory, and non-respiratory motor drives during breathing or other behaviors). This tonic and phasic expression of PMUSCLE acts to stiffen and enlarge the airspace. Key pharyngeal muscles include those of the tongue and soft palate innervated by the hypoglossal and trigeminal motor nuclei in the medulla and pons via cranial nerves XII and V respectively.