RAT ISOSORBIDE DINITRATE (ISDN) MODEL
Animals
Studies are conducted in adult male and female Sprague Dawley rats (Envigo) in an AAALAC-accredited facility with approval from an Institutional Animal Care and Use Committee, and implemented in accordance with the Guide for the Care and Use of Laboratory Animals 8th Edition (National Research Council, 2011) with standards set by the National Institutes of Health.
Model induction
This rat model of vascular headache is characterized by facial mechanical allodynia following the administration of a nitric oxide donor (NO), isosorbide dinitrate (ISDN), consistent with the development of headache in human subjects following administration of NO donors (Dallel et al., 2018; Iversen et al., 1989).
ISDN (10 mg/kg) is dissolved in saline by stirring on a hot plate and is administered intraperitoneally (IP) at a dose volume of 10 mL/kg body weight.
Study design
In the ISDN model, facial mechanical allodynia using von Frey filaments is assessed in cohorts of appropriate group sizes determined by power analysis. Male and female rats (n=10-15) are evaluated in separate cohorts. Dose-responses are investigated, and vehicle and positive control groups are included to establish the validity of the experiment. The experimenter is blinded to the treatments, and dosing is performed by an independent experimenter.
On test days, rats are placed in Bowman restrainers for facial mechanical sensitivity testing. The von Frey filaments are applied to the periorbital region as shown in De Logu et al., 2019.
Experimental outcomes
Facial mechanical allodynia testing using von Frey filaments
Facial mechanical allodynia is assessed by applying a series of calibrated von Frey filaments to the periorbital region on the medial/left side of the forehead above the eye. Baselines are recorded prior to ISDN administration and rats that have a baseline facial sensitivity threshold < 8 g are excluded from the study. Animals are balanced across treatment groups based on body weight and baseline facial mechanical allodynia threshold.
References
Dallel R, Descheemaeker A, Luccarini P (2018). Recurrent administration of the nitric oxide donor, isosorbide dinitrate, induces a persistent cephalic cutaneous hypersensitivity: a model for migraine progression. Cephalalgia 38(4):776-785. PMID: 28565942 DOI: 10.1177/0333102417714032
De Logu F, Landini L, Janal MN, Li Puma S, De Cesaris F, Geppetti P, Nassini R (2019). Migraine-provoking substances evoke periorbital allodynia in mice. Journal of Headache Pain 20(1):18. PMID: 30764776 DOI: 10.1186/s10194-019-0968-1
Iversen HK, Olesen J, Tfelt-Hansen P (1989). Intravenous nitroglycerin as an experimental model of vascular headache. Basic Characteristics. Pain 38(1):17-24. PMID: 2506503 DOI: 10.1016/0304-3959(89)90067-5
National Research Council (2011). Guide for the Care and Use of Laboratory Animals: Eighth Edition. Washington, DC: The National Academies Press
This work was conducted by PsychoGenics Inc. (Paramus, NJ) in collaboration with PSPP, NINDS, NIH under contract # 75N95019D00026 and 75N95024D00038