Dark-Cycle Video Surveillance of Sexual Performances of Normal and Diabetic Rats

Tong, Yat Ching; Hung, Ying Cho; Lin, Shinn Nan; Cheng, Juei Tang

doi:10.1159/000282843

Cited by 7 publications

(8 citation statements)

References 14 publications

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“…Several studies have demonstrated a loss or reduction in the activity of the hypothalamic-pituitary-gonadal axis and sexual behavior in rats with insulin-dependent diabetes (23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36). Although some of these indexes of reproductive function can be improved with insulin treatment, others remain compromised despite treatment (27).…”

Section: Discussionmentioning

confidence: 99%

“…Control injections consisted of vehicle with 2.5 mg/ml goat IgG (Chemicon, Santa Cruz, CA). The experimental treatments consisted of a combination of two separate, affinity-purified GALP antibodies (goat polyclonal antibodies against GALP 41-60 [CILDLWKAIDG LPYSRSPRMT] and GALP [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] [CLHLSSKANQGRKTDSALAIL]; Bethyl Labs, Montgomery, TX) combined and reconstituted at 2.5 mg/ml in artificial cerebrospinal fluid (aCSF). Both antibodies were shown by enzyme-linked immunosorbent assay, Western blot, and immunocytochemical analyses to be specific for full-length GALP and not to bind nonspecifically to other hypothalamic neuropeptides, such as galanin, oxytocin, neurophysin, vasopressin, or neuropeptide Y (data not shown).…”

Section: Methodsmentioning

confidence: 99%

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Galanin-Like Peptide Rescues Reproductive Function in the Diabetic Rat

et al. 2005

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Galanin-like peptide (GALP) is expressed in the hypothalamic arcuate nucleus and is regulated by leptin and insulin. Centrally administered GALP stimulates gonadotropin secretion and sexual behavior in the rat. Type 1 diabetes is associated with reduced expression of GALP, as well as an overall decline in reproductive function. We postulated that tonic activity of GALP in the brain is required to sustain normal reproductive activity. To test this hypothesis, we examined whether central (intracerebroventricular) immunoblockade of GALP would reduce sexual behaviors and serum levels of luteinizing hormone (LH) in normal adult male rats. We found that GALP antibody reversibly reduced serum levels of LH and abolished male sexual behaviors (P < 0.05 and 0.001, respectively). Second, we tested whether intracerebroventricular GALP could restore normal plasma LH levels and sexual behavior in diabetic animals. We compared groups of diabetic rats that received intracerebroventricular GALP or vehicle and found that GALP increased serum levels of LH and sexual behavior. Third, we examined whether intracerebroventricular administration of affinity-purified GALP antibody could block the effect of insulin and leptin in reversing the effects of diabetes on LH and sexual behavior. We found that treatment of diabetic animals with insulin and leptin nearly normalized LH levels and sexual behaviors; however, this effect was attenuated by intracerebroventricular administration of GALP antibody (P < 0.05). These observations demonstrate that endogenous GALP provides trophic support to the neuroendocrine reproductive axis, including sexual behavior. Diabetes 54:2471-2476, 2005 D eviations of normal metabolism and nutrition can disrupt reproduction. The activity of the reproductive axis may be altered by changes in circulating levels of metabolic hormones such as leptin and insulin, whose blood levels typically reflect an animal's metabolic status and fuel reserves (1). Reproductive dysfunction is common in metabolic diseases, such as type 1 and type 2 diabetes (2,3; rev. in 4). Sexual dysfunction in diabetes is thought to be attributable to a central neuropathy (5); however, the cellular and molecular etiology of this phenomenon is unknown. It seems plausible that the reproductive dysfunction associated with diabetes is caused by a disruption in the cellular and molecular targets in the brain for insulin and other metabolic factors that may be altered in diabetes. Neurons that produce galanin-like peptide (GALP) are prime candidates for mediating this phenomenon.GALP is a neuropeptide that is expressed in the arcuate nucleus of the hypothalamus and has been implicated in the regulation of gonadotropin-releasing hormone. Central infusions of GALP stimulate the secretion of gonadotropin-releasing hormone as well as luteinizing hormone (LH) and induce all aspects of sexual behavior in the male rat (6 -9). GALP has also been implicated in the neuroendocrine regulation of feeding and body weight (7,10 -12). Fasting and uncontrolled diabetes...

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Galanin-Like Peptide Rescues Reproductive Function in the Diabetic Rat

et al. 2005

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“…The cage was illuminated with infrared light from an Ikegami IR-light illuminator. The activities were filmed with an Ikegami ICD-42 black and white CCD video camera and recorded with a Panasonic AG-6024 24-hour video recorder [22].…”

Section: Dark-cycle Sexual Activity Recordingmentioning

confidence: 99%

“…To evaluate the male sexual activities of the rats, the copulatory test would be started 60 min after giving the 7th, 30th, and 90th doses of drugs or saline of intromission divided by the number of mounts with or without intromission) as described in our previous reports [22,24].…”

Section: Analysis Of Sexual Activitiesmentioning

confidence: 99%

Effects of Losartan on the Sexual Behavior of Male Rats

Chan

Liu

Tong³

et al. 1999

Pharmacology

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Many commonly used antihypertensive drugs such as diuretics and beta-blockers can interfere with sexual function in both sexes, causing loss of libido, impairment of erectile function and ejaculation in men, and delay or prevent orgasm in women. Newly developed antihypertensive drugs should ideally not interfere with the patients’ quality of life including sexual function. This study examined the effects of losartan, a nonpeptide, specific antagonist for type I angiotensin II receptors, on the male sexual behavior of rats. Spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto (WKY) rats were treated with losartan 30 mg/ kg/day or saline control for 7, 30 and 90 days. Dark-cycle video recording was used to analyze the male sexual activities of the rats. No significant alteration in male sexual performance was observed after 7 and 30 days of treatment with losartan. In contrast, SHRs treated with propranolol 5 mg/kg/day showed increases in intromission latency, ejaculation latency and postejaculatory period indicating decreased libido and erectile and ejaculatory function. Upon completion of 90 days of losartan administration, the mount latency of the SHR was significantly increased, suggesting a decrease in libido although other parameters were unchanged and there was no effect in WKY rats. It is therefore concluded that losartan may have an advantage in preservation of sexual function when used clinically for the treatment of hypertensive disorders.

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“…By dark-cycle video surveillance of animal sexual behavior [18], we reported that treatment with losartan caused little change in the erectile and ejaculatory performances of both SHR and WKY rats. The only positive observation was that after 90 days of losartan treatment, the libido of SHR rats was depressed [19].…”

Section: Discussionmentioning

confidence: 94%

Effect of N-(Biphenylyl-Methyl)Imidazole, a Type 1 Angiotensin II Receptor Inhibitor,on the Co ntractile Function of the Rat Corpus cavernosum

et al. 2000

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The effect of N-(biphenylyl-methyl)imidazole, losartan potassium, a newly developed antihypertensive type 1 angiotensin II receptor antagonist on the rat erectile function, was studied. Sexually active 9-week-old male spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats were given losartan 60 mg/kg intraperitoneal injections. Mean blood pressure (MBP) dropped significantly in both SHR and WKY rats (for SHR: from 140 ± 8 to 114 ± 5 mm Hg, p < 0.05, n = 8; for WKY: from 113 ± 7 to 79 ± 9 mm Hg, p < 0.05, n = 8). On the contrary, the intracavernous pressure (ICP) of SHR and WKY rats did not differ significantly from that of the corresponding controls receiving saline injections (p > 0.05, n = 8 for each group). For the chronic study, the rats were fed with losartan 30 mg/kg/day for 30 days. MBP decreased significantly in SHR but not in WKY rats (for SHR: from 137 ± 7 to 113 ± 5 mm Hg, p < 0.05, n = 8; for WKY: from 110 ± 6 to 107 ± 5 mm Hg, p > 0.05, n = 8). The ICP of the losartan-treated rats was not significantly different from that of control rats (p > 0.05, n = 8 for each group). In contrast, WKY rats receiving guanethidine 1 mg/kg/day for 30 days showed significantly decreased ICP. Angiotensin II (10^–9–10^–5 M) and losartan (10^–9– 10^–5 M) did not induce significant contractile responses of the cavernosal strip when tested in vitro. On the other hand, methoxamine 10^–4 M induced good contractile responses. In conclusion, the present study demonstrated that angiotensin II did not cause significant change in the contractile status of rat corpus cavernosum. Correspondingly, the type 1 angiotensin II inhibitor effectively lowered blood pressure but did not affect cavernosal contractile function, thus is useful clinically in the treatment of hypertensive disorders without significant detrimental effects on male sexual function.

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Dark-Cycle Video Surveillance of Sexual Performances of Normal and Diabetic Rats

Cited by 7 publications

References 14 publications

Galanin-Like Peptide Rescues Reproductive Function in the Diabetic Rat

Galanin-Like Peptide Rescues Reproductive Function in the Diabetic Rat

Effects of Losartan on the Sexual Behavior of Male Rats

Effect of N-(Biphenylyl-Methyl)Imidazole, a Type 1 Angiotensin II Receptor Inhibitor,on the Co ntractile Function of the Rat Corpus cavernosum

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