Antagonism of peripheral 5-HT4 receptors reduces visceral and cutaneous pain in mice, and induces visceral analgesia after simultaneous inactivation of 5-HT3 receptors

doi:10.1016/S0006-8993(97)01510-2

Brain Research

Volume 788, Issues 1–2, 30 March 1998, Pages 20-24

https://doi.org/10.1016/S0006-8993(97)01510-2 Get rights and content

Abstract

The role of 5-HT₄ receptors on cutaneous and visceral pain remains largely unexplored. The objective of this study was to establish the activity profile of SDZ 205-557, a 5-HT₄ antagonist, on cutaneous (hotplate) and visceral (writhing) models of pain, after peripheral administration. Since SDZ 205-557 possesses some affinity for 5-HT₃ receptors at high doses, nociceptive effects of a 1:1 combination of SDZ 205-557 and MDL 72222, a 5-HT₃ antagonist, were also evaluated. Drugs were injected 30 min before tests (0, 0.001, 0.01, 0.1 or 1 mg/kg IP). A hypoalgesic effect of SDZ 205-557 on cutaneous pain was found at 0.1 and 1 mg/kg doses, as revealed through an enhanced nociceptive threshold in rats placed on the hotplate. This effect was likely mediated through inactivation of peripheral 5-HT₄ receptors. After the 1:1 combination, the hypoalgesic effect disappeared, which indicates that simultaneous inactivation of 5-HT₃ and 5-HT₄ receptors antagonized peripherally 5-HT₄-mediated hypoalgesia by an unknown mechanism. SDZ 205-557 also induced hypoalgesia in the writhing test over the entire dose range tested, and visceral hypoalgesia turned out to be analgesia after 1:1 combination. In summary, findings of the present study imply that: i) antagonism of 5-HT₄ receptors mediates antinociception in enteric viscera and, to a lesser extent, in cutaneous terminals, and ii) dual inactivation of both 5-HT₄ and 5-HT₃ receptors induces visceral analgesia, a fact which might have clinical importance.

Introduction

The neural distribution of 5-HT₄ receptors suggests a role in nociception. These receptors are highly expressed in limbic areas, periaqueductal grey matter and sensory terminals 4, 24, 27, 28. However, the role of 5-HT₄ receptors on cutaneous and visceral pain has been little explored. Nonselective 5-HT₄ agonists such as BIMU1, BIMU8 and cisapride appear to have analgesic properties after systemic administration, and SDZ 205-557, 5-HT₄ antagonist, blocks the antinociceptive effects of these compounds, as evaluated by hotplate, writhing and paw-pressure tests [12]. However, all these effects are seen after high doses, which are outside the effective dose range of 5-HT₄ ligands. It is well known that, at high doses, most 5-HT₄ ligands possess affinity for 5-HT₃ receptors as well, whose effects could mask 5-HT₄-mediated effects [12]. Recently it has been proposed that selective inactivation of peripheral 5-HT₄ receptors reduces inflammatory pain, as revealed through attenuation of formalin-induced hyperalgesia by GR113808A, a highly selective 5-HT₄ antagonist [3].

The objective of this study was to establish the activity profile of SDZ 205-557, 5-HT₄ antagonist, on cutaneous and visceral nociception, as measured by hotplate and writhing tests, respectively. SDZ 205-557 is a selective 5-HT₄ antagonist, although it possesses some affinity for 5-HT₃ receptors at high doses. For this reason, the nociceptive effects of a 1:1 combination of SDZ 205-557 and MDL 72222, a 5-HT₃ antagonist, were also evaluated in order to establish whether or not SDZ 205-557-mediated effects were due to 5-HT₄ antagonism alone. MDL 72222 is a highly selective 5-HT₃ ligand, with a dissociation constant below 10⁻⁹ M 8, 20, 25.

Section snippets

Animals

Male albino mice (30–35 g) from the breeding colony of the Faculty of Medicine of the University of Seville, Spain, were housed in groups of ten at the beginning of the experiment. They were allowed to adapt to the vivarium for at least one week. For the hotplate study, they were randomly allocated in two groups: SDZ 205-557-treated (5-HT₄ group, n=40), and 1:1 combination (1:1 group, n=40). For the writhing test study, they were randomly assigned to two groups: SDZ 205-557-treated (5-HT₄

Hotplate test

The nociceptive threshold was found to be significantly longer at 0.1 and 1 mg/kg in the 5-HT₄ group vs. controls (p<0.01), and changes followed an inverted U-shaped curve. The 1:1 combination did not significantly alter nociceptive threshold latencies over the entire dose range tested. The nociceptive threshold was found to be significantly longer in the 5-HT₄ group than in the 1:1 group at the 0.1 mg/kg dose (t=5.1; p<0.001). Values of the nociceptive threshold in both groups after every dose

Hotplate test

Findings indicated that SDZ 205-557 induced hypoalgesia in mice placed on the hotplate test, but it was limited to the highest doses tested (0.1 and 1 mg/kg). Since the strongest hypoalgesic effect was observed at a moderate dose (0.1 mg/kg), SDZ 205-557-induced hypoalgesia appears to be mediated through selective inactivation of 5-HT₄ receptors. In this context, a peripherally active 5-HT₄ antagonist (GR113808A) has shown to be effective in attenuating formalin-induced inflammatory pain,

Acknowledgements

This study was supported by a grant to E.F.E. from Consejerı́a de Educación y Ciencia, Andalusian Government, Spain (group No. CVI 0127, PAI). The authors thank Dr. M. Isabel Serrano (Sevilla, Spain) for her helpful assistance, as well as Drs. L. Stinus (Bordeaux, France) and G. Alvarez de Toledo (Sevilla, Spain) for the generous gift of surgery material.

References (28)

E.O. Alvarez et al.
Histamine in dorsal and ventral hippocampus: II. Effects of H1 and H2 histamine antagonists on exploratory behavior in male rats
Physiol. Behav.
(1986)
R.M. Danzebrink et al.
Evidence that spinal 5-HT₁, 5-HT₂ and 5-HT₃ receptor subtypes modulate responses to noxious colorectal distension in the rat
Brain Res.
(1991)
G.J. Doak et al.
Formalin-induced nociceptive behavior and edema: involvement of multiple peripheral 5-hydroxytryptamine receptor subtype
Neuroscience
(1997)
R.M. Eglen et al.
Central 5-HT₄ receptors
Tr. Pharmacol. Sci.
(1995)
E.F. Espejo et al.
Structure of the rat's behaviour in the hot plate test
Behav. Brain Res.
(1993)
C. Ghelardini et al.
Central cholinergic antinociception induced by 5HT₄ agonists: BIMU 1 and BIMU 8
Life Sci.
(1996)
J. Giordano et al.
Peripherally administered serotonin 5-HT₃ receptor antagonists reduce inflammatory pain in rats
Eur. J. Pharmacol.
(1989)
S.R. Glaum et al.
Reversal of the antinociceptive effects of intrathecally administered serotonin in the rat by selective 5-HT₃ receptor antagonist
Neurosci. Lett.
(1988)
A.J. Greenshaw
Behavioral pharmacology of 5-HT₃ receptor antagonists: a critical update on therapeutic potential
Tr. Neurosci.
(1993)
G. Guilbaud et al.
Evidence for peripheral serotonergic mechanisms in the early sensitization after carrageenin-induced inflammation: electrophysiological studies in the ventrobasal complex of the rat thalamus using a potent specific antagonist of peripheral 5-HT receptors
Brain Res.
(1989)

S.T. Meller et al.

The peripheral nociceptive actions of intravenously administered 5-HT in the rat requires dual activation of both 5-HT₂ and 5-HT₃ receptor subtypes

Brain Res.

(1991)

P.C. Moser

The effect of 5-HT₃ antagonists on the writhing response in mice

Gen. Pharmacol.

(1995)

P.K. Eide et al.

The role of 5-hydroxytryptamine (5-HT) receptor subtypes and plasticity in the 5-HT systems in the regulation of nociceptive sensitivity

Cephalalgia

(1993)

E.F. Espejo et al.

Effects of morphine and naloxone on behavior in the hot plate test: an ethopharmacological study in the rat

Psychopharmacology

(1994)

Cited by (53)

Serotonin enhances oxybuprocaine- and proxymetacaine-induced cutaneous analgesia in rats
2019, European Journal of Pharmacology
Citation Excerpt :
It is likely that serotonin does improve the proxymetacaine or oxybuprocaine function due to proxymetacaine's or oxybuprocaine's Na+ channel blocking effect, which consists a superior blocking mechanism of the neural transmission in the periphery. The potential mechanism of the serotonin effect by which serotonergic 5-HT1A and 5-HT4 receptors involve in analgesia (Espejo and Gil, 1998; Tian et al., 2016), apart from its action as a vasoconstrictor (Newman et al., 1996; Xia et al., 2013), should be considered in the future. For instance, serotonin 5-HT4 receptors antagonism mediates cutaneous antinociception in mice (Espejo and Gil, 1998).
The aim of the study was to investigate the analgesic effects of adding serotonin to oxybuprocaine or proxymetacaine preparations. We employed a rat model of the cutaneous trunci muscle reflex (CTMR) to conduct the dose-response curves and duration of drugs (oxybuprocaine, proxymetacaine, or serotonin) as an infiltrative anesthetic. The use of isobolographic methods to analyze the drug-drug interactions. We showed that oxybuprocaine and proxymetacaine, as well as serotonin produced dose-dependent skin antinociception. On the basis of 50% effective dose (ED₅₀), the rank order of drug potency was serotonin [7.22 (6.45–8.09) μmol/kg] < oxybuprocaine [1.03 (0.93–1.15) μmol/kg] < proxymetacaine [0.59 (0.53–0.66) μmol/kg] (P < 0.01 for each comparison). The sensory block duration of serotonin was longer (P < 0.01) than that of oxybuprocaine or proxymetacaine at the equipotent doses (ED₂₅, ED₅₀, and ED₇₅). The mixture of serotonin with oxybuprocaine or proxymetacaine produced a better analgesic effect than the drug itself. We have concluded that oxybuprocaine, proxymetacaine, or serotonin displays dose-related cutaneous analgesia. Oxybuprocaine or proxymetacaine is more potent and has a shorter duration of cutaneous analgesia than serotonin. Serotonin produces a synergistic antinociceptive interaction with oxybuprocaine or proxymetacaine.
Serotonin and nociception: From nociceptive transduction at the periphery to pain modulation from the brain
2019, The Serotonin System: History, Neuropharmacology, and Pathology
Pain is an ancient physiological system of alert, protecting organisms from real or potential bodily damage. Pain experience is a complex phenomenon involving the orchestration of different multilayer mechanisms accounting for the transduction, transmission, and modulation of the nociceptive input. Early evidence from genetic and pharmacological manipulation studies of serotonin signaling in acute and chronic pain models have converged to support the notion that serotonin is a pivotal neuromodulator of nociception at several of its generation and controlling steps. Its actions seem to be complex and depend on a number of factors such as the site of action, the cell type, and the type of receptor targeted, exerting both facilitatory and inhibitory actions. Assuming this complexity may significantly hamper a quick overview of the topic by a nonspecialized audience, this chapter aims to summarize our current knowledge about the role of serotonin in pain (including nociceptive transduction, transmission, and modulation from the brain) and the contribution of its dysregulation to pain disturbances during chronic pain. Implications of this knowledge for pharmacological management of pain and drug development are discussed as well.
Spinal 5-HT<inf>4</inf> and 5-HT<inf>6</inf> receptors contribute to the maintenance of neuropathic pain in rats
2017, Pharmacological Reports
Citation Excerpt :
This interpretation is reinforced by our findings showing that ML10302 (a 5‐HT4 receptor agonist, [26,27]) and WAY208466 (a 5‐HT6 receptor agonist, [28]) prevented the antiallodynic effects of GR-113808 and SB-258585, respectively. Our data in a neuropathic pain model agree with several observations in different models of inflammatory pain in which selective 5-HT4 receptor antagonists such as GR113808A, GR-125487 or SDZ 205-557 (peripheral or intrathecal administration) reduce nociceptive behavior induced by formalin [21,38] or acetic acid [39] in the rat. Furthermore, GR-113808 is able to diminish the peripheral pronociceptive effect of fluoxetine in the formalin test [22].
Nerve injury promotes release of 5-HT at the spinal cord. Once released, 5-HT may produce antinociceptive or pronociceptive effects depending of the nature of 5-HT receptors. The purpose of this study was to investigate the participation of spinal 5-HT₄ and 5-HT₆ receptors in the maintenance of neuropathic pain in rats.
Tactile allodynia was measured using von Frey hairs in male Wistar rats subjected to L5-L6 spinal nerve injury. Selective 5-HT₄ (GR-113808, 0.01–10 nmol/rat) and 5-HT₆ (SB-258585, 1–1000 nmol/rat) receptor antagonists were administered intrathecally to nerve injured rats. Likewise, the most effective dose of 5-HT₄ (1 nmol/rat) and 5-HT₆ (100 nmol/rat) antagonists were co-administered with their respective agonists (ML-10302, 10–100 nmol/rat and WAY-208466, 100–1000 nmol/rat, respectively). Spinal cord protein expression of both receptors was determined by western blot.
Intrathecal administration of 5-HT₄ or 5-HT₆ receptor antagonists, but not vehicle, decreased in a dose-dependent manner tactile allodynia in neuropathic rats. Moreover, intrathecal co-administration with the agonists prevented in a dose-dependent manner the antagonists-induced antiallodynic effect. Both 5-HT₄ and 5-HT₆ receptors were expressed in the spinal cord of naïve, sham and neuropathic rats. Nerve injury did not modify expression of any receptor.
Data suggests that spinal 5-HT₄ and 5-HT₆ receptors are expressed in dorsal spinal cord and they participate in the maintenance of neuropathic pain in rats. In this regard, blockade of these receptors could be a useful strategy to treat neuropathic pain states.
The 5-HT<inf>4</inf> receptor-mediated inhibition of visceral nociceptive neurons in the rat caudal ventrolateral medulla
2017, Neuroscience
Citation Excerpt :
Taken together, these data encourage the expectation that activation of the aforementioned receptors would augment rather than inhibit the excitability of gut intrinsic and extrinsic afferents and therefore would facilitate visceral nociception (Grundy, 2002). The hypoalgesia that was produced by peripherally administered 5-HT4 antagonists in the writhing test is consistent with this proposal (Espejo and Gil, 1998; Hinschberger et al., 2003). All the above imply that if the 5-HT4 receptors located on the gut sensory afferents were involved in the action of intravenous BIMU8, their stimulation could either promote or impede the drug-induced antinociception that we observed.
Activation of the serotonin type 4 (5-HT₄) receptors has been reported to improve abdominal pain in patients with functional gastrointestinal disorders and reduce visceral nociception in animal models. Earlier studies have proposed that 5-HT₄ agonist can produce visceral analgesia by acting at the supraspinal level, but the underlying neuronal mechanisms remain unclear. The caudal ventrolateral medulla (CVLM) is the first site for processing of visceral nociceptive signals ascending via spinal pathways and an important component of the endogenous pain modulatory system. Therefore, the objective of the present study was to examine whether activation of 5-HT₄ receptors can affect the visceral pain-related neurons in the CVLM. In urethane-anesthetized adult male Wistar rats, we evaluated the effects of a 5-HT₄ receptor agonist, BIMU8 on ongoing firing of the CVLM neurons and their excitatory responses to noxious colorectal distension (CRD, 80 mmHg). The drug’s effect was also tested on blood pressure reactions induced by CRD–a general physiological measure of visceral nociception. Intravenous administration of BIMU8 (0.5, 1 or 2 mg/kg) produced dose-dependent suppression of both the ongoing and CRD-evoked activities of the CVLM neurons and simultaneously attenuated the depressor hemodynamic reaction to CRD. The compound’s inhibitory effect was almost completely eliminated by intracerebroventricular pretreatment with GR113808, a selective 5-HT₄ antagonist, indicating the preferential involvement of supraspinal 5-HT₄ receptors. Results indicate that visceral nociceptive transmission through the caudal medulla is negatively modulated by descending 5-HT₄-dependent mechanisms. These findings can contribute to a deeper understanding of supraspinal processing of pain signals from the abdomen.
Role of peripheral and spinal 5-HT<inf>2B</inf> receptors in formalin-induced nociception
2012, Pharmacology Biochemistry and Behavior
Citation Excerpt :
Mounting evidence indicates that peripheral 5-HT may produce hyperalgesia by activating multiple 5-HT receptor subtypes. According to the transduction mechanisms, it has been demonstrated that peripheral activation of 5-HT3 (Abbott et al., 1996; Doak and Sawynok, 1997; Sufka et al., 1992; Parada et al., 2001; Zeitz et al., 2002), 5-HT4 (Doak and Sawynok, 1997; Espejo and Gil, 1998; Parada et al., 2001), 5-HT6 (Castañeda-Corral et al., 2009) and 5-HT7 (Meuser et al., 2002; Rocha-González et al., 2005) receptors leads to nociception. In the case of 5-HT2 receptors, there are reports showing that activation of 5-HT2A (Tokunaga et al., 1998; Okamoto et al., 2002, 2005) and 5-HT2C receptors (Nakajima et al., 2009) leads to nociception.
In this study we assessed the role of local peripheral and spinal serotonin 2B (5-HT_2B) receptors in rats submitted to the formalin test. For this, local peripheral ipsilateral, but not contralateral, administration of the highly selective 5-HT_2B receptor antagonist 2-amino-4-(4-fluoronaphth-1-yl)-6-isopropylpyridine (RS-127445, 0.01–1 nmol/paw) significantly prevented 1% formalin-induced flinching behavior. Moreover, local peripheral ipsilateral, but not contralateral, of the selective 5-HT₂ receptor agonist (±)-2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI, 1–10 nmol/paw) augmented 0.5% formalin-induced nociceptive behavior. The local pronociceptive effect of the 5-HT₂ receptor agonist DOI (10 nmol/paw) was significantly prevented by the local injection of RS-127445 (0.01 nmol/paw). Moreover, intrathecal injection of the selective 5-HT_2B receptor antagonist RS-127445 (0.1–10 nmol/rat) also prevented 1% formalin-induced nociceptive behavior. In contrast, spinal injection of the 5-HT₂ receptor agonist DOI (1–10 nmol/rat) significantly increased flinching behavior induced by 0.5% formalin. The spinal pronociceptive effect of the 5-HT₂ receptor agonist DOI (10 nmol/rat) was prevented by the intrathecal injection of the 5-HT_2B receptor antagonist RS-127445 (0.1 nmol/rat). Our results suggest that the 5-HT_2B receptors play a pronociceptive role in peripheral as well as spinal sites in the rat formalin test. 5-HT_2B receptors could be a target to develop analgesic drugs.
Spinal 5-HT receptors that contribute to the pain-relieving effects of spinal cord stimulation in a rat model of neuropathy
2011, Pain
Spinal cord stimulation (SCS) is extensively employed in the management of neuropathic pain, but the underlying mechanisms are only partially understood. Recently, we demonstrated that the pain-relieving effect of SCS appears to involve the spinal serotonin system, and the present study aimed at identifying the types of the spinal serotonin receptors involved. Experiments were performed on rats with neuropathy produced by partial ligation of the sciatic nerve. Tactile sensitivity was assessed using von Frey filaments, and cold and heat sensitivity with cold spray and radiant heat, respectively. Selective 5-HT receptor antagonists, methiothepin (5-HT₁,₆,₇), ketanserin tartrate (5-HT_2A), TICM (5-HT₃), SDZ-205,557 (5-HT₄), as well as receptor agonists, α-m-5-HT (5-HT₂), m-CPBG (5-HT₃) in per se ineffective doses, or vehicle, were administrated intrathecally 5 minutes prior to the application of SCS. Ketanserin and SDZ-205,557 significantly attenuated the suppressive effect of SCS on tactile hypersensitivity, while methiothepin and TICM were ineffective. The suppressive effect on cold hypersensitivity of SCS was counteracted by ketanserin only. None of the 5-HT receptor antagonists attenuated the suppressive effect on heat hyperalgesia of SCS. Subeffective doses of α-m-5-HT and m-CPBG enhanced the suppressive effect of SCS on tactile hypersensitivity. The enhancing effect of m-CPBG was abolished by a γ-aminobutyric acid (GABA)_A or GABA_B antagonist intrathecally. These results suggest that the activation of 5-HT_2A, 5-HT₃, and 5-HT₄ receptors plays an important role in SCS-induced relief of neuropathic pain. The activation of 5-HT₃ receptors appears to operate via spinal GABAergic interneurons.

View all citing articles on Scopus

View full text

Research reportAntagonism of peripheral 5-HT4 receptors reduces visceral and cutaneous pain in mice, and induces visceral analgesia after simultaneous inactivation of 5-HT3 receptors

Abstract

Introduction

Section snippets

Animals

Hotplate test

Hotplate test

Acknowledgements

Physiol. Behav.

Brain Res.

Neuroscience

Tr. Pharmacol. Sci.

Behav. Brain Res.

Life Sci.

Eur. J. Pharmacol.

Neurosci. Lett.

Tr. Neurosci.

Brain Res.

Brain Res.

Gen. Pharmacol.

The role of 5-hydroxytryptamine (5-HT) receptor subtypes and plasticity in the 5-HT systems in the regulation of nociceptive sensitivity

Cephalalgia

Effects of morphine and naloxone on behavior in the hot plate test: an ethopharmacological study in the rat

Psychopharmacology

Research report
Antagonism of peripheral 5-HT₄ receptors reduces visceral and cutaneous pain in mice, and induces visceral analgesia after simultaneous inactivation of 5-HT₃ receptors