PT  - JOURNAL ARTICLE
AU  - Zhang, Zhaocun
AU  - Slater, Richard C.
AU  - Ferroni, Matthew C.
AU  - Kadow, Brian T.
AU  - Lyon, Timothy D.
AU  - Shen, Bing
AU  - Xiao, Zhiying
AU  - Wang, Jicheng
AU  - Kang, Audry
AU  - Roppolo, James R.
AU  - de Groat, William C.
AU  - Tai, Changfeng
TI  - Role of <em>µ</em>, <em>κ</em>, and <em>δ</em> Opioid Receptors in Tibial Inhibition of Bladder Overactivity in Cats
AID  - 10.1124/jpet.115.226845
DP  - 2015 Nov 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 228--234
VI  - 355
IP  - 2
4099  - http://jpet.aspetjournals.org/content/355/2/228.short
4100  - http://jpet.aspetjournals.org/content/355/2/228.full
SO  - J Pharmacol Exp Ther2015 Nov 01; 355
AB  - In α-chloralose anesthetized cats, we examined the role of opioid receptor (OR) subtypes (µ, κ, and δ) in tibial nerve stimulation (TNS)-induced inhibition of bladder overactivity elicited by intravesical infusion of 0.25% acetic acid (AA). The sensitivity of TNS inhibition to cumulative i.v. doses of selective OR antagonists (cyprodime for µ, nor-binaltorphimine for κ, or naltrindole for δ ORs) was tested. Naloxone (1 mg/kg, i.v., an antagonist for µ, κ, and δ ORs) was administered at the end of each experiment. AA caused bladder overactivity and significantly (P < 0.01) reduced bladder capacity to 21.1% ± 2.6% of the saline control. TNS at 2 or 4 times threshold (T) intensity for inducing toe movement significantly (P < 0.01) restored bladder capacity to 52.9% ± 3.6% or 57.4% ± 4.6% of control, respectively. Cyprodime (0.3–1.0 mg/kg) completely removed TNS inhibition without changing AA control capacity. Nor-binaltorphimine (3–10 mg/kg) also completely reversed TNS inhibition and significantly (P < 0.05) increased AA control capacity. Naltrindole (1–10 mg/kg) reduced (P < 0.05) TNS inhibition but significantly (P < 0.05) increased AA control capacity. Naloxone (1 mg/kg) had no effect in cyprodime pretreated cats, but it reversed the nor-binaltorphimine–induced increase in bladder capacity and eliminated the TNS inhibition remaining in naltrindole pretreated cats. These results indicate a major role of µ and κ ORs in TNS inhibition, whereas δ ORs play a minor role. Meanwhile, κ and δ ORs also have an excitatory role in irritation-induced bladder overactivity.