PMC

(A and B) EFS-mediated cAMP (A) and cGMP (B) production were measured in phenylephrine-precontracted CCSs of Ada^–/– and Ada⁺ mice with or without MRS1706, ZM241389, and/or l-NAME treatment. Data are means ± SEM (n = 4). *P < 0.05, versus wild-type with EFS; **P < 0.05 versus Ada^–/– with EFS alone; ***P < 0.05 versus wild-type with EFS alone.

(A) Ada^–/– mice exhibited prolonged penile erections, lasting 8–72 hours. Priapic erections were never observed in control Ada⁺ male mice. (B and C) Ada^–/– mice displayed hypersensitivity to EFS in both dosage-dependent (B) and frequency-dependent (C) manners. Data are means ± SEM. *P < 0.05, Ada^–/– versus Ada⁺. n = 5–10.

(A) The extent of adenosine-induced CCS relaxation in wild-type mice with theophylline treatment was measured by a force transducer. Data are means ± SEM (n = 5). *P < 0.05 versus untreated; **P < 0.05 versus adenosine alone. (B) Adenosine-induced CCS relaxation in wild-type, A₁R^–/–, A_2AR^–/–, A_2BR^–/–, and A₃R^–/– mice was measured by a force transducer. Data are means ± SEM (n = 5–10). *P < 0.005 versus wild-type. (C) Adenosine-mediated cAMP production of CCSs from wild-type and A_2BR^–/– mice. Some of the CCSs from wild-type mice were treated with l-NAME or MRS1706. Data are means ± SEM (n = 6–7). *P < 0.05 versus wild-type treated with adenosine alone.

(A and B) CCSs of wild-type mice were treated with different concentrations of adenosine in the presence or absence of DCF (5 μM; A) or with 100 μM adenosine in the presence of different concentrations of DCF (0–100 μM; B). The resulting adenosine-induced CCS relaxation was monitored by force transducer. Data are means ± SEM. *P < 0.05 versus adenosine alone; **P < 0.05 versus untreated.

(A–D) Histological examination of the vascular structures in the corpus spongiosum. (A and B) H&E staining. (C and D) Anti–α-SMA immunohistochemical staining. Arrowheads indicate intimal thickening with smooth muscle hypertrophy of the vascular wall in the deep dorsal vein; arrows indicate muscular hypertrophy of the arterial vascular wall. (E–H) Fibrosis in corpus spongiosum (E and F) and corpus cavernosum (G and H) visualized by Masson trichrome staining. Arrowheads denote the extensive fibrosis with extension into the intima of the deep dorsal vein; arrows indicate fibrosis around the lumen of the artery. Original magnification, ×100 (A–D); ×200 (E–H).

(A) Adenosine levels were elevated in the penes of SCD transgenic mice. Data are means ± SEM (n = 5–6). *P < 0.005 versus control. (B) Increased CCS relaxation by EFS in SCD transgenic mice. Data are means ± SEM (n = 5). P < 0.05, SCD transgenic versus control. (C–E) Prolonged penile erection in SCD transgenic mice is due to A_2BR signaling. EFS-induced relaxation in CCSs (C), duration of relaxation (D), and the combination of force and duration (area under baseline; E) were measured by force transducer in mice left untreated or treated with PEG-ADA, MRS1706, or ZM241389. Data are means ± SEM (n = 5). *P < 0.05 versus control; **P < 0.05, versus untreated SCD transgenic; ***P < 0.05 versus untreated control.

(A) Adenosine levels were elevated in the penes of Ada^–/– mice. Inset bar graph shows the average adenosine levels from 3 Ada^–/– mice and 3 wild-type mice. Data are means ± SEM (n = 3). *P < 0.005 versus Ada⁺. (B) The prolonged penile erection in Ada^–/– mice was corrected by intraperitoneal injection of PEG-ADA. n = 3–5. (C) Representative recordings of EFS-induced CCS relaxation (5 V and 30 Hz) using 10 μM phenylephrine–precontracted CCSs of Ada⁺ mice and Ada^–/– mice treated with or without PEG-ADA. (D–F) Average EFS-induced relaxation from the phenylephrine-precontracted CCSs of Ada⁺ mice, Ada^–/– mice, and Ada^–/– mice treated with PEG-ADA. EFS-induced changes in the force of CCS relaxation (D), the duration of relaxation (E), and the combination of force and duration (area under baseline; F). Data are means ± SEM (n = 5–6). *P < 0.05 versus Ada⁺; **P < 0.05 versus untreated Ada⁺; ***P < 0.05 versus untreated Ada^–/–.

(A) Adenosine receptor mRNA expression profile in purified primary CCSMCs were determine by quantitative real-time RT-PCR. nd, not determined. (B) cAMP levels of CCSMCs from wild-type mouse penes in the presence of different concentrations of adenosine with or without specific adenosine receptor agonists or antagonists. Data are means ± SEM. *P < 0.05 versus adenosine alone. (C) cAMP levels of CCSMCs from wild-type and A_2BR^–/– mice treated with adenosine, NECA, or forskolin. Data are means ± SEM (n = 4). *P < 0.05 versus untreated wild-type; **P < 0.05 versus untreated A_2BR^–/–. (D) cGMP levels in CCSs of wild-type and A_2BR^–/– mice treated with l-NAME or MRS1706. Data are means ± SEM (n = 6–7). *P < 0.05 versus wild-type treated with adenosine alone. (E) cGMP levels in CCSMCs of wild-type and A_2BR^–/– mice treated with the indicated compounds. Data are means ± SEM. *P < 0.05 versus respective control.