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Yao J, Li X, Wu GY, Wu B, Long JH, Wang PJ, Liu SL, Gao J, Sui JF. The Anterior Insula and its Projection to the Prelimbic Cortex are Involved in the Regulation of 5-HT-Induced Itch. Neurosci Bull 2023; 39:1807-1822. [PMID: 37553505 PMCID: PMC10661608 DOI: 10.1007/s12264-023-01093-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 04/12/2023] [Indexed: 08/10/2023] Open
Abstract
Itch is an unpleasant sensation that urges people and animals to scratch. Neuroimaging studies on itch have yielded extensive correlations with diverse cortical and subcortical regions, including the insular lobe. However, the role and functional specificity of the insular cortex (IC) and its subdivisions in itch mediation remains unclear. Here, we demonstrated by immunohistochemistry and fiber photometry tests, that neurons in both the anterior insular cortex (AIC) and the posterior insular cortex (PIC) are activated during acute itch processes. Pharmacogenetic experiments revealed that nonselective inhibition of global AIC neurons, or selective inhibition of the activity of glutaminergic neurons in the AIC, reduced the scratching behaviors induced by intradermal injection of 5-hydroxytryptamine (5-HT), but not those induced by compound 48/80. However, both nonselective inhibition of global PIC neurons and selective inhibition of glutaminergic neurons in the PIC failed to affect the itching-scratching behaviors induced by either 5-HT or compound 48/80. In addition, pharmacogenetic inhibition of AIC glutaminergic neurons effectively blocked itch-associated conditioned place aversion behavior, and inhibition of AIC glutaminergic neurons projecting to the prelimbic cortex significantly suppressed 5-HT-evoked scratching. These findings provide preliminary evidence that the AIC is involved, at least partially via aversive emotion mediation, in the regulation of 5-HT-, but not compound 48/80-induced itch.
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Affiliation(s)
- Juan Yao
- Experimental Center of Basic Medicine, Army Medical University, Chongqing, 400038, China
- Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing, 400038, China
| | - Xuan Li
- Experimental Center of Basic Medicine, Army Medical University, Chongqing, 400038, China
| | - Guang-Yan Wu
- Experimental Center of Basic Medicine, Army Medical University, Chongqing, 400038, China
| | - Bing Wu
- Experimental Center of Basic Medicine, Army Medical University, Chongqing, 400038, China
| | - Jun-Hui Long
- Department of Dermatology, The 958th Army Hospital of the People's Liberation Army, Chongqing, 400020, China
| | - Pu-Jun Wang
- Department of Dermatology, The 958th Army Hospital of the People's Liberation Army, Chongqing, 400020, China
| | - Shu-Lei Liu
- Department of Dermatology, The 958th Army Hospital of the People's Liberation Army, Chongqing, 400020, China
| | - Jie Gao
- State Key Laboratory of Trauma, Burns and Combined Injury, Army Medical Centre of the PLA, Institute of Surgery Research, Daping Hospital, Army Medical University, Chongqing, 400042, China.
| | - Jian-Feng Sui
- Experimental Center of Basic Medicine, Army Medical University, Chongqing, 400038, China.
- Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing, 400038, China.
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Long JH, Wang PJ, Li ZF, Yao J, Li X, Wu B, Sui JF, Liao J, Wang P, Li XF, Liu SL. Dysgranular retrosplenial cortex modulates histaminergic and nonhistaminergic itch processing. Behav Brain Res 2023; 443:114306. [PMID: 36682500 DOI: 10.1016/j.bbr.2023.114306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/22/2023]
Abstract
Itch is an unpleasant sensation followed by an intense desire to scratch. Previous researches have advanced our understanding about the role of anterior cingulate cortex and prelimbic cortex in itch modulation, whereas little is known about the effects of retrosplenial cortex (RSC) during this process. Here we firstly confirmed that the neuronal activity of dysgranular RSC (RSCd) is significantly elevated during itch-scratching processing through c-Fos immunohistochemistry and fiber photometry recording. Then with designer receptors exclusively activated by designer drugs approaches, we found that pharmacogenetic inhibition of global RSCd neurons attenuated the number of scratching bouts as well as the cumulative duration of scratching bouts elicited by both 5-HT or compound 48/80 injection into rats' nape or cheek; selective inhibition of the pyramidal neurons in RSCd, or of the excitatory projections from caudal anterior cingulate cortex (cACC) to RSCd, demonstrated the similar effects of decreasing itch-related scratching induced by both 5-HT or compound 48/80. Pharmacogenetic intervention of the neuronal or circuitry activities did not affect rats' motor ability. This study presents direct evidence that pyramidal neurons in RSCd, and the excitatory projection from cACC to RSCd are critically involved in central regulation of both histaminergic and nonhistaminergic itch.
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Affiliation(s)
- Jun-Hui Long
- Department of Dermatology, The 958th Army Hospital of the Chinese People's Liberation Army, China
| | - Pu-Jun Wang
- Department of Dermatology, The 958th Army Hospital of the Chinese People's Liberation Army, China
| | - Zhi-Fang Li
- Department of Foreign Languages, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Juan Yao
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Xuan Li
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Bing Wu
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Jian-Feng Sui
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Jun Liao
- Department of Dermatology, The 958th Army Hospital of the Chinese People's Liberation Army, China
| | - Ping Wang
- Department of Dermatology, The 958th Army Hospital of the Chinese People's Liberation Army, China
| | - Xiao-Feng Li
- Department of Radiology, the Third Affiliated Hospital of Chongqing Medical University, Chongqing 401120, China.
| | - Shu-Lei Liu
- Department of Dermatology, The 958th Army Hospital of the Chinese People's Liberation Army, China.
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