Junichi Hachisuka, MD, PhD

Junichi Hachisuka


Research Assistant Professor, Neurobiology

PhD – Kyushu University (2011)
MD – Nagoya University (2002)

Office: W1453 BSTWR
203 Lothrop Street,
Pittsburgh, PA 15213-2548

Telephone: 412-648-8182
E-mail: juh49@pitt.edu

Neural Circuit for Itch and Pain:

The somatosensory system is a complex system that responds to changes to the surface or internal state of the body, giving rise to the perceptions of touch, pain, itch and temperature. Stimuli are initially detected at the organs such as skin, and this information is transmitted to the spinal cord. Spinal microcircuits modulate and integrate those signals and this information is transmitted to the brain via spinal projection neurons. However, the neural circuits through which spinal cord neurons encode and discriminate pain, itch, touch and temperature are almost completely unknown. Itch, in particular, is an aversive sensation that can ruin a patient’s quality of life, and for which there are no good treatments. Therefore, the long-term goal of my research is to address how somatosensory inputs are integrated and processed in the spinal cord, with a particular focus on itch.

To tackle the question how spinal microcircuits modulate somatosensory input, I developed a novel electrophysiological technique which allows us, for the first time, to record neural activity of a specific population of spinal cord neurons that are labeled with fluorescent marker while we are applying natural stimulation onto the skin (Hachisuka et al., 2016). Thus, I am now poised to address questions about spinal circuitry that were previously elusive.

Using this new method, I am trying answer following questions: (1) how itch and pain are encoded in the spinal projection neurons; (2) how itch and pain signal are modulated by the spinal interneurons.


Semi-intact ex vivo approach to investigate spinal somatosensory circuits.

Hachisuka J, Baumbauer KM, Omori Y, Snyder LM, Koerber HR, Ross SE.

 2016 Dec 19;5. pii: e22866.

Insight into B5-I spinal interneurons and their role in the inhibition of itch and pain.

Chiang MC, Hachisuka J, Todd AJ, Ross SE.

 2016 Mar;157(3):544-5.

Keratinocytes can modulate and directly initiate nociceptive responses.

Baumbauer KM, DeBerry JJ, Adelman PC, Miller RH, Hachisuka J, Lee KH, Ross SE, Koerber HR, Davis BM, Albers KM.

 2015 Sep 2;4.

STAT3-dependent reactive astrogliosis in the spinal dorsal horn underlies chronic itch.

Shiratori-Hayashi M, Koga K, Tozaki-Saitoh H, Kohro Y, Toyonaga H, Yamaguchi C, Hasegawa A, Nakahara T, Hachisuka J, Akira S, Okano H, Furue M, Inoue K, Tsuda M.

 2015 Aug;21(8):927-31.

Antioxidant Opuntia ficus-indica Extract Activates AHR-NRF2 Signaling and Upregulates Filaggrin and Loricrin Expression in Human Keratinocytes.

Nakahara T, Mitoma C, Hashimoto-Hachiya A, Takahara M, Tsuji G, Uchi H, Yan X, Hachisuka J, Chiba T, Esaki H, Kido-Nakahara M, Furue M.

 2015 Oct;18(10):1143-9.

Understanding the switch from pain-to-itch in dermatitis.

Hachisuka J, Ross SE.

 2014 Sep 5;579:188-9.

Spinal Microcircuits and the Regulation of Itch.

Ross SE, Hachisuka J, Todd AJ.

 Carstens EAkiyama T, editors. Itch: Mechanisms and Treatment. Boca Raton (FL): CRC Press/Taylor & Francis; 2014. Chapter 20. Frontiers in Neuroscience.

Dynorphin acts as a neuromodulator to inhibit itch in the dorsal horn of the spinal cord.

Kardon AP, Polgár E, Hachisuka J, Snyder LM, Cameron D, Savage S, Cai X, Karnup S, Fan CR, Hemenway GM, Bernard CS, Schwartz ES, Nagase H, Schwarzer C, Watanabe M, Furuta T, Kaneko T, Koerber HR, Todd AJ, Ross SE.

 2014 May 7;82(3):573-86.

Aberrant expression of S100A6 and matrix metalloproteinase 9, but not S100A2, S100A4, and S100A7, is associated with epidermal carcinogenesis.

Zhu L, Kohda F, Nakahara T, Chiba T, Tsuji G, Hachisuka J, Ito T, Tu Y, Moroi Y, Uchi H, Furue M.

 2013 Dec;72(3):311-9.

Verruciform xanthoma of the glans penis mimicking squamous cell carcinoma – role of scavenger receptor positive macrophages.

Miake S, Nakahara T, Kurihara Y, Hachisuka J, Moroi Y, Furue M.

 2012 May-Jun;22(3):391-2.

Congenital benign mesenchymoma on the palm.

Kudo K, Nakahara T, Hachisuka J, Masuda T, Miake S, Moroi Y, Kiryu H, Furue M.

 2012 Mar-Apr;22(2):256-7.

Combination cryosurgery with hyperthermia in the management of skin metastasis from breast cancer: A case report.

Hachisuka J, Doi K, Furue M.


Successful treatment of epidermal growth factor receptor inhibitor-induced periungual inflammation with adapalene.

Hachisuka J, Doi K, Moroi Y, Furue M.

 2011 May;3(2):130-6.

Effect of adapalene on cetuximab-induced painful periungual inflammation.

Hachisuka J, Yunotani S, Shidahara S, Moroi Y, Furue M.

 2011 Feb;64(2):e20-1.

Are lifetime prevalence of impetigo, molluscum and herpes infection really increased in children having atopic dermatitis?

Hayashida S, Furusho N, Uchi H, Miyazaki S, Eiraku K, Gondo C, Tsuji G, Hachisuka J, Fukagawa S, Kido M, Nakahara T, Moroi Y, Hayashi J, Hagihara A, Furue M.

 2010 Dec;60(3):173-8.

Responsiveness of C neurons in rat dorsal root ganglion to 5-hydroxytryptamine-induced pruritic stimuli in vivo.

Hachisuka J, Furue H, Furue M, Yoshimura M.

 2010 Jul;104(1):271-9.

Severity of disease, rather than xerosis, correlates with pruritus in patients with atopic dermatitis.

Hachisuka J, Takeuchi S, Kido M, Fukiwake N, Furue M.

 2009 Apr;48(4):374-8.

Enhancement of Ca2+-induced Ca2+ release by cyclic ADP-ribose in frog motor nerve terminals.

Hachisuka J, Soga-Sakakibara S, Kubota M, Narita K, Kuba K.

 2007 Apr 25;146(1):123-34.

A case of Carney complex.

Hachisuka J, Ichikawa M, Moroi Y, Urabe K, Furue M.

 2006 Dec;45(12):1406-7.

Functional coupling of Ca(2+) channels to ryanodine receptors at presynaptic terminals. Amplification of exocytosis and plasticity.

Narita K, Akita T, Hachisuka J, Huang S, Ochi K, Kuba K.

 2000 Apr;115(4):519-32.