Roles of Ca_v3.2 and TRPA1 channels targeted by hydrogen sulfide in pancreatic nociceptive processing in mice with or without acute pancreatitis

Abstract

Hydrogen sulfide (H(2)S), formed by multiple enzymes, including cystathionine-γ-lyase (CSE), targets Ca(v)3.2 T-type Ca(2+) channels (T channels) and transient receptor potential ankyrin-1 (TRPA1), facilitating somatic pain. Pancreatitis-related pain also appears to involve activation of T channels by H(2)S formed by the upregulated CSE. Therefore, this study investigates the roles of the Ca(v)3.2 isoform and/or TRPA1 in pancreatic nociception in the absence and presence of pancreatitis. In anesthetized mice, AP18, a TRPA1 inhibitor, abolished the Fos expression in the spinal dorsal horn caused by injection of a TRPA1 agonist into the pancreatic duct. As did mibefradil, a T-channel inhibitor, in our previous report, AP18 prevented the Fos expression following ductal NaHS, an H(2)S donor. In the mice with cerulein-induced acute pancreatitis, the referred hyperalgesia was suppressed by NNC 55-0396 (NNC), a selective T-channel inhibitor; zinc chloride; or ascorbic acid, known to inhibit Ca(v)3.2 selectively among three T-channel isoforms; and knockdown of Ca(v)3.2. In contrast, AP18 and knockdown of TRPA1 had no significant effect on the cerulein-induced referred hyperalgesia, although they significantly potentiated the antihyperalgesic effect of NNC at a subeffective dose. TRPA1 but not Ca(v)3.2 in the dorsal root ganglia was downregulated at a protein level in mice with cerulein-induced pancreatitis. The data indicate that TRPA1 and Ca(v)3.2 mediate the exogenous H(2)S-induced pancreatic nociception in naïve mice and suggest that, in the mice with pancreatitis, Ca(v)3.2 targeted by H(2)S primarily participates in the pancreatic pain, whereas TRPA1 is downregulated and plays a secondary role in pancreatic nociceptive signaling.

Polaprezinc attenuates cyclophosphamide-induced cystitis and related bladder pain in mice

“…3), supporting our previous report that Ca v 3.2 channels play a critical role in the maintenance of cyclophosphamide-induced bladder pain (8). The present results are consistent with our previous reports that zinc chloride suppresses the Ca v 3.2-dependent colonic pain following intracolonic administration of an H 2 S donor (10) and the cerulein-induced pancreatitis-related pain in which the H 2 S/Ca v 3.2 pathway plays a pronociceptive role (33). The preventive and therapeutic effects of polaprezinc on the cystitis-related pain is not secondary to impairment of motor coordination in consideration of the results of the rota-rod test (see Fig.…”

Tacrolimus Triggers Transient Receptor Potential Vanilloid-1-Dependent Relapse of Pancreatitis-Related Pain in Mice

“…3b). It is to be noted that the same dose, 10 mg/kg of the T-type Ca 2+ channel inhibitor NNC 55-0396, administered i.p., suppresses the cerulein-induced pancreatitis-related referred hyperalgesia and intracolonic NaHS-induced visceral pain-like behavior/referred hyperalgesia in mice, which involve the enhanced activity of Ca v 3.2 T-type Ca 2+ channels [4,14]. The reason why tacrolimus facilitated referred hyperalgesia in the recovery phase (Fig.…”

“…Among various “pronociceptive” ion channels expressed in nociceptors, transient receptor potential vanilloid-1 (TRPV1) channels and Ca v 3.2 T-type Ca 2+ channels play critical roles in the development of pancreatitis-related pain [1,2,3,4]. TRPV1 is directly phosphorylated and sensitized by protein kinase C (PKC), particularly following the activation of proteinase-activated receptor-2 (PAR2), a Gq protein-coupled receptor, known to be expressed in nociceptors [5].…”

Hydrogen Sulfide and T-Type Ca²⁺ Channels in Pain Processing, Neuronal Differentiation and Neuroendocrine Secretion

“…In mice or rats, intraplantar and intracolonic administration of NaHS, an H 2 S donor, evokes mechanical hyperalgesia/allodynia and visceral nociceptive behavior accompanied by re- 198 ferred hyperalgesia, respectively, which are blocked by Ttype Ca 2+ blockers or gene silencing of Ca v 3.2 [8,11,29,34,35] . In the mice with cerulein-induced pancreatitis and with cyclophosphamide-induced cystitis, CSE protein is markedly upregulated in the pancreas and bladder, respectively, and the concomitant pancreatic and bladder pain are abolished by a CSE inhibitor or distinct T-type Ca 2+ channel blockers, and by knockdown of Ca v 3.2 in DRG by intrathecal administration of the Ca v 3.2-targeting antisense oligodeoxynucleotide [26,27,36] . The CSE inhibitor, T-type Ca 2+ channel blockers and knockdown of Ca v 3.2 also suppress the neuropathic hyperalgesia induced by L5 spinal nerve injury in rats, and upregulation of Ca v 3.2 channels, but not CSE, at protein levels are detectable in the DRG following the development of neuropathy [31] .…”