1.3.4 Cell-Cell Communication in Taste Buds:
Activation of Type II cells by taste stimuli causes release of ATP through pannexin hemichannels and/or CALMH1 channels. The released ATP or sour stimuli can activate Type III cells and causes release of different hormones such as 5-HT and NE via Ca2+-dependent exocytosis. In some instances NE is co-released with 5-HT (Dvoryanchikov et al., 2007; Huang et al., 2008a).
The ATP released by Type II taste cells acts as a paracrine as well as an autocrine signaling molecule. The ATP activates gustatory nerve fibers and Type III cells by binding to the P2X (on nerve fibers) or P2Y (Type III cells) receptors and also binds to purinergic receptors (P2Y) on Type II cells and promotes further release of …show more content…
Signals in this portion of the ascending lemniscal pathway are proposed to be important for the detection and discrimination of taste stimuli (Roper, 2009; Spector and Glendenning, 2009). In rodents this ascending pathway is relayed in the parabrachial nucleus of the pons. However, in humans and other primates it connects directly to the relay neurons in the parvocellular division of the ventroposteromedial thalamic nucleus, or taste thalamic nucleus (Whitehead and Finger, 2008). Taste information from this nucleus then goes to a region of cerebral cortex, known as gustatory cortex. Human neuroimaging studies show that a small number of neurons in the gustatory cortex represent taste quality (Schoenfield et al., 2004). From gustatory cortex, taste signals are transmitted to a secondary gustatory cortex, also known as orbifrontal cortex. Sensory modalities of taste, vision, and olfaction are proposed to converge in this region and construct the perception of flavor. Neurons of the secondary gustatory cortex are also proposed to be involved in satiety. Taste signal from orbifrontal cortex goes to amygdala and lateral hypothalamus, which is proposed to impart hedonic value to taste sensations and integrate taste information in the context of energy need and reward (Hofmann et al., 2011). Finally, cortical taste areas send afferents to the NTS/parabrachial nucleus allowing top-down modulation of gustatory processing at the level of the brainstem (Roper,
Activation of Type II cells by taste stimuli causes release of ATP through pannexin hemichannels and/or CALMH1 channels. The released ATP or sour stimuli can activate Type III cells and causes release of different hormones such as 5-HT and NE via Ca2+-dependent exocytosis. In some instances NE is co-released with 5-HT (Dvoryanchikov et al., 2007; Huang et al., 2008a).
The ATP released by Type II taste cells acts as a paracrine as well as an autocrine signaling molecule. The ATP activates gustatory nerve fibers and Type III cells by binding to the P2X (on nerve fibers) or P2Y (Type III cells) receptors and also binds to purinergic receptors (P2Y) on Type II cells and promotes further release of …show more content…
Signals in this portion of the ascending lemniscal pathway are proposed to be important for the detection and discrimination of taste stimuli (Roper, 2009; Spector and Glendenning, 2009). In rodents this ascending pathway is relayed in the parabrachial nucleus of the pons. However, in humans and other primates it connects directly to the relay neurons in the parvocellular division of the ventroposteromedial thalamic nucleus, or taste thalamic nucleus (Whitehead and Finger, 2008). Taste information from this nucleus then goes to a region of cerebral cortex, known as gustatory cortex. Human neuroimaging studies show that a small number of neurons in the gustatory cortex represent taste quality (Schoenfield et al., 2004). From gustatory cortex, taste signals are transmitted to a secondary gustatory cortex, also known as orbifrontal cortex. Sensory modalities of taste, vision, and olfaction are proposed to converge in this region and construct the perception of flavor. Neurons of the secondary gustatory cortex are also proposed to be involved in satiety. Taste signal from orbifrontal cortex goes to amygdala and lateral hypothalamus, which is proposed to impart hedonic value to taste sensations and integrate taste information in the context of energy need and reward (Hofmann et al., 2011). Finally, cortical taste areas send afferents to the NTS/parabrachial nucleus allowing top-down modulation of gustatory processing at the level of the brainstem (Roper,