Increased plasma norepinephrine concentration in cats with interstitial cystitis.

Area of Science:

• Urology
• Veterinary Medicine
• Neuroendocrinology

Background:

• Interstitial cystitis (IC) is a chronic condition affecting humans and cats (feline interstitial cystitis or FIC).
• FIC symptoms may worsen with stress, implicating the sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA) axis.
• Previous research noted SNS abnormalities in human IC patients, but data on catecholamine levels and HPA function in feline IC were lacking.

Purpose of the Study:

• To investigate the role of the SNS and HPA axis in feline interstitial cystitis.
• To measure plasma catecholamine concentrations and their metabolites in cats with FIC.
• To assess HPA axis function by measuring plasma adenocorticotropic hormone (ACTH) and cortisol response to corticotropin-releasing factor (CRF) infusion.

Main Methods:

• Eight healthy cats and eight cats with FIC were studied.
• Plasma samples were analyzed using high-performance liquid chromatography for norepinephrine, dihydroxyphenylglycol, epinephrine, dihydroxyphenylalanine, dopamine, and dihydroxyphenylacetic acid.
• Four cats per group received an infusion of ovine CRF, with blood samples collected over 120 minutes to measure ACTH and cortisol.

Main Results:

• Cats with FIC exhibited significantly increased plasma norepinephrine and dihydroxyphenylglycol concentrations.
• A trend toward increased plasma epinephrine was observed in cats with FIC.
• No significant changes were found in dihydroxyphenylalanine, dopamine, dihydroxyphenylacetic acid, ACTH, or cortisol levels between groups.

Conclusions:

• The findings support and expand upon previous research indicating heightened sympathetic activity in feline interstitial cystitis.
• Increased sympathetic tone may contribute to the pathophysiology of FIC.
• Further research into the neuroendocrine mechanisms of FIC is warranted.