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Increased cavernosal relaxation in type 2 diabetic Goto‐Kakizaki rats
Author(s) -
Carneiro Fernando S.,
Giachini Fernanda R. C.,
Carneiro Zidonia N.,
Lima Victor V.,
Ergul Adviye,
Tostes Rita C.,
Webb R. C.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1226.13
Subject(s) - medicine , endocrinology , phenylephrine , insulin resistance , diabetes mellitus , sodium nitroprusside , hyperinsulinemia , streptozotocin , prediabetes , type 2 diabetes , insulin , blood pressure , nitric oxide
Diabetes mellitus (DM) is an important risk factor for erectile dysfunction (ED). Commonly used experimental models of diabetes include the chemically‐induced streptozotocin model of type 1 diabetes, which displays highly elevated glucose levels, or obesity‐induced models such as Zucker rats and db/db mice. Aim: In this study we evaluated cavernosal reactivity in Goto‐Kakizaki (GK) rats, which are not obese and display moderate changes in blood glucose, insulin resistance and blood pressure. This model is particularly relevant to ED studies since the great majority of patients with prediabetes or type 2 diabetes display mild defects in glucose‐stimulated insulin secretion, insulin resistance, hyperinsulinemia and hyperglycemia. Methods and Results: Male GK and Wistar control (C) rats were used at 18 weeks of age (n=5 and 7, respectively). Sympathetic‐mediated contractile responses (induced by electrical field stimulation (EFS), 50V, 1 ms pulse, 1–64 Hz) were attenuated in cavernosal strips from GK rats (C: 6.3±0.7 vs GK: 2.5±0.4, mN). Similarly, cavernosum from GK rats showed decreased contractions to phenylephrine (C: 7.0±0.4 vs GK: 1.9±0.2, mN) and KCl (C: 4.6±0.3 vs GK: 1.4±0.2, mN). Non‐adrenergic‐non‐cholinergic (NANC)‐induced relaxation was increased in cavernosal strips from GK rats (Figure 1), but relaxation to sodium nitroprusside was not. Conclusion: In contrast to other models of diabetes, GK rats exhibit changes in cavernosal reactivity that would facilitate erectile responses. This may be due to compensatory mechanisms activated at this stage of diabetes.