Exploring the neurobiology of the premonitory phase of migraine preclinically - a role for hypothalamic kappa opioid receptors?

Abstract

Background: The migraine premonitory phase is characterized in part by increased thirst, urination and yawning. Imaging studies show that the hypothalamus is activated in the premonitory phase. Stress is a well know migraine initiation factor which was demonstrated to engage dynorphin/kappa opioid receptors (KOR) signaling in several brain regions, including the hypothalamus. This study proposes the exploration of the possible link between hypothalamic KOR and migraine premonitory symptoms in rodent models.

Methods: Rats were treated systemically with the KOR agonist U-69,593 followed by yawning and urination monitoring. Apomorphine, a dopamine D1/2 agonist, was used as a positive control for yawning behaviors. Urination and water consumption following systemic administration of U-69,593 was also assessed. To examine if KOR activation specifically in the hypothalamus can promote premonitory symptoms, AAV8-hSyn-DIO-hM4Di (Gi-DREADD)-mCherry viral vector was microinjected into the right arcuate nucleus (ARC) of female and male KOR^CRE or KOR^WT mice. Four weeks after the injection, clozapine N-oxide (CNO) was administered systemically followed by the assessment of urination, water consumption and tactile sensory response.

Results: Systemic administration of U-69,593 increased urination but did not produce yawning in rats. Systemic KOR agonist also increased urination in mice as well as water consumption. Cell specific Gi-DREADD activation (i.e., inhibition through Gi-coupled signaling) of KOR^CRE neurons in the ARC also increased water consumption and the total volume of urine in mice but did not affect tactile sensory responses.

Conclusion: Our studies in rodents identified the KOR in a hypothalamic region as a mechanism that promotes behaviors consistent with clinically-observed premonitory symptoms of migraine, including increased thirst and urination but not yawning. Importantly, these behaviors occurred in the absence of pain responses, consistent with the emergence of the premonitory phase before the headache phase. Early intervention for preventive treatment even before the headache phase may be achievable by targeting the hypothalamic KOR.

Keywords: Arcuate nucleus; Hypothalamus; Kappa opioid receptors (KOR); Migraine prevention; Premonitory phase; Premonitory symptoms.

Fig. 1

Systemic KOR agonist, U-69,593, failed to induce yawning behavior but increased urination in both female and male rats. A The number of yawning events and, B the increase in urination were evaluated for 120 min after a single subcutaneous administration of U-69,593 at 0.56 mg/kg, apomorphine at 0.05 mg/kg (a non-selective dopamine agonist used as a positive control for yawning) and vehicle-control. The number of yawning was quantified in 30-min intervals. Urination was quantified as the difference between the weight of the individual absorbable underpads before drug administration and 120 min after testing. Female and male data were combined. Data are presented as mean ± SEM and analyzed using two-way (A) or one-way (B) ANOVA followed by Tukey’s multiple comparison test with * representing p < 0.05 in comparison with the control group (n = 12; 6 females/group and 6 males/group)

Fig. 2

Systemic U-69,593 increased water consumption and urination in female and male mice. Mice were individually placed in metabolic chambers and received a single subcutaneous administration of U-69,593 at 30 mg/kg or vehicle-control. A Water consumption and B volume of urine, as outcome measurements of thirst and polyuria, respectively, were evaluated for 120 min after treatment. C Linear regression was performed to evaluate the correlation between water consumption and urination in U-69,593-treated mice. Female and male data were combined. Data are presented as mean ± SEM and analyzed using one-way ANOVA followed by Sidak’s multiple comparison test with * representing p < 0.05 compared to the control group (n = 12; 6 females/group and 6 males/group)

Fig. 3

Chemogenetic manipulation of KOR^CRE neurons in the ARC increased water consumption and urination in both female and male mice. KOR^CRE or KOR^WT female and male mice were individually placed in metabolic chambers and received a single dose of CNO (DREADD specific agonist; 5 mg/kg, i.p.) four weeks after stereotaxic administration of AAV8-hSyn-DIO-hM4D(Gi)-mCherry virus (100 nL) into the right ARC. A Water consumption and B volume of urine, as outcome measurements of thirst and polyuria, respectively, were evaluated for 120 min after treatment. C Linear regression was performed to evaluate the correlation between water consumption and urination in KOR.^CRE mice. Female and male data were combined. Data are presented as mean ± SEM and analyzed using one-way ANOVA followed by Sidak’s multiple comparison test (A) and (B) with * representing p < 0.05 compared to the control group (n = 10 – 13; Panel A: 5 females/6 males WT and 6 females/7 males HET; Panels B and C: 5 females/5 males WT and 6 females/7 males HET)

Fig. 4

Chemogenetic manipulation of KOR^CRE neurons in the ARC did not modify periorbital and hindpaw tactile responses in female and male mice. Frequency of response to tactile stimulation in the A periorbital and B hindpaw region was performed before AAV virus injection (BL1), 4 weeks after the injection (BL2), and hourly up to 5 h after administration of CNO (5 mg/kg, i.p.) in KOR^CRE or KOR^WT mice. Data from female and male mice were combined and are presented as mean ± SEM. Statistical analysis was performed using two-way ANOVA followed by Sidak’s multiple comparison test (A) and (B) (n = 13; 7 females/6 males WT and 6 females/7 males HET)