2005 Fiscal Year Final Research Report Summary
Responses of histamine-sensitive neurons to mechanical, chemical, and thermal stimuli and their receptors
| Project/Area Number |
16591573
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Anesthesiology/Resuscitation studies
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| Research Institution | Kansai Coll. of Oriental Med., Dept. of Physiology |
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Principal Investigator |
KASHIBA Hitoshi Kansai Coll. of Oriental Med., Dept. of Physiology, Associate Prof., 鍼灸学部, 助教授 (10185754)
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| Co-Investigator(Kenkyū-buntansha) |
OHSHIMA Minoru Kansai Coll. of Oriental Med., Dept, Physiology, Assistant, 鍼灸学部, 助手 (20342230)
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| Project Period (FY) |
2004 – 2005
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| Keywords | histamine / HI receptor / primary afferent neurons / dorsal horn neurons / patch clamp recoding methods / neuropeptides |
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| Research Abstract |
The receptors for histamine are divided into four types, H1, H2, H3, and H4 receptors. Histamine is thought to deliver itch sensation via HI receptors on primary sensory neurons. Our previous studies showed that H1 receptor-expressing dorsal root ganglion neurons (about 15-20%) are unmyelinated in the guinea pig. However, these may not be peptidergic and capsaicin-sensitive neurons. The profiles of H1 receptor-expressing neurons in the guinea pig are partly incompatible for the physiological data of histamine-sensitive neurons in the rat. In this study, we examined the expression of H1 receptor in the rat primary sensory neurons by immunohistochemistry and transcriptase-polymerase chain reaction (RT-PCR). The immunoreactivity for H1 receptor was seen in 20-30% of the dorsal root ganglions. These neurons were also labeled by isolectin-B4, which is a marker of unmyelinated sensory neurons. Furthermore, half of these neurons were positive to substance P, TRPV1 (transient receptor potential channel vanilloid subfamily 1), and P2X3 (ionotropic ATP receptor subtype 3). Positive signals of H1 receptor mRNA in rat dorsal root and trigeminal ganglia were clearly detected by RT-PCR, but were weaker than those of GAPDH mRNA. In contrast, H1 receptor mRNA signals in the guinea pig sensory ganglia were more intense than those of GAPDH mRNA. A few of vagal afferent neurons (about 5% of nodose ganglion neurons) were also immunoreactive to H1 receptors in the rat. No expression of H1 receptor mRNA was seen in the guinea pig nodose ganglion in our previous study. These results suggest that the expression pattern of histamine H1 receptor in primary sensory neurons of the rat is partially different from that of the guinea pig.
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Research Products
(11 results)
