OBJECTIVETo research the mechanism of dopamine (DA) controlled memory in mice.

METHODSMice received i.p. injection of scopolamine (0.3 mg/kg, SCOP 0.3, and 3.0mg/kg, SCOP 3.0, respectively, n = 10) and saline (NS, n = 10) for 60 days in experiment 1. Memory of mice was detected by dark avoidance behavior in the 53" d and the 60"' d. Animals were sacrificed after the memory test; brain tissues were processed for Fos-ir and TH-ir by immunohistochemistry. Mice were divided into four groups according results of expri-ment 1, they received i.p. injection of apomorphine (0.1 mg/kg, APO 0.1, 0.5 mg/kg, APO 0.5, and 2.0 mg/kg, APO2.0 respectively, n = 10).

RESULTSMemory was inhibited in mice injected scopolamine 3.0 mg/kg. Latency was significantly less than in NS group, only 1/ 4 that of NS group (P > 0.05). The number of mistake of SCOP 3.0 group increased about four times than that of NS group (P > 0.05). But there was no difference of latency and number of mistake between SCOP 0.3 and NS group in expriment 1. Scopolamine-induced memory deficit was associated with decreased cellular activation, indicated by Fos immunoreactive (ir) staining, in NAcc CA1 and CA3 (P < 0.05), and also associated with decreases in the number of cells labeled for tyrosine hydroxylase (TH-ir), the rate limiting enzyme for dopamine conversion (P < 0.01) and the number of cells co-labeled for TH-ir/Fos-ir (P <0.01) in the ventral tegmental area(VTA), apomorphine lessened scopolamine-induced memory deficit in experiment 2. The number of cells co-labeled for TH-ir/Fos-ir (P <, 0.05) was increased in VTA after apomorphine treatment.

CONCLUSIONApomorphine lessened scopolamine-induced memory deficit in mice by increasing DA activities in VTA.

Animals ; Apomorphine ; pharmacology ; Disease Models, Animal ; Dopamine Agonists ; pharmacology ; Male ; Memory Disorders ; chemically induced ; drug therapy ; Mice ; Scopolamine Hydrobromide ; toxicity

OBJECTIVETo set the measuring method of tyrosine hydroxylase activity in the brain of conscious rats.

METHODBy using microdialysis and High Performance Liquid Chromatography-Electrochemical Detector system, the 3, 4-dihydrioxphenylalanine (DOPA) formation in the striatum of 6-hydroxdopamine-pretreated rats during infusion of an L-aromatic amino-acid decarboxylase inhibitor (NSD1015) was monitored.

RESULTThe absence of DOPA in dialysates of 6-hydroxdopamine-pretreated rats, the measurable DOPA and the steady decreasing of 3,4-dihydroxyphenylacetic acid(DOPAC) during infusion of NSD1015 and the disappearance of DOPA after administration of alpha-methyl-rho-tyrosine indicated that the dialyzed DOPA was derived from dopaminergic nerve terminals. After intraperitoneal administration of dopamine receptor agonist apomorphine the DOPA output was deseased. After intraperitoneal administration of dopamine recepter antagonist haloperidol, the DOPA output was increased. The study showed that twenty-four hours ofter implantation of the probe with infusion of 0.01 mmol.L-1 NSD1015, the DOPA level in the striatum of 6-hydroxdopamine-pretreated rats was 0.39 +/- 0.12 pmol/min (X +/- S, n = 5).

CONCLUSIONThe DOPA concentration in striatal dialysates could be considered as an index of tyrosion hydroxlase activity during infusion of 0.01 mM NSD1015. The method in vivo to monitor tyrosine hydroxlase activity in the brain is reliable.

Animals ; Apomorphine ; pharmacology ; Brain ; enzymology ; Dihydroxyphenylalanine ; metabolism ; Dopamine Agonists ; pharmacology ; Dopamine Antagonists ; pharmacology ; Female ; Haloperidol ; pharmacology ; Male ; Microdialysis ; Rats ; Rats, Sprague-Dawley ; Tyrosine 3-Monooxygenase ; metabolism

OBJECTIVETo investigate the inhibitory effect of antisense oligonucleotides (ODN) on dopamine transporter (DAT) in rats and observe the response of the rats to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).

METHODSThe cannula was implanted in the substantia nigra compacta under a rat stereotaxic device, through which drugs were used. The rats with successful operation were divided randomly into four groups, and received injection of antisense, sense, missense oligonucleotides and saline respectively, in the substantia nigra compacta of each rat via the cannula, followed by MPTP (30 mg/kg) injection. Behavior of the rats was observed and immunohistochemistry was carried out to check the expression of DAT and apoptosis of dopamine cell.

RESULTSThe expression of DAT (positive unit, PU) in the substantia nigra compacta in rats was 6.65+/- 1.67 in the antisense ODN group, 12.41+/- 2.46 in saline group, 11.45+/- 1.17 in sense ODN group, and 10.35+/- 2.89 in missense ODN group. The expression of DAT was lower in the antisense ODN group than that of the other three groups (P< 0.01). The rotation of the rats induced by apomorphine was slower than that of the other three groups(P< 0.05). The apoptotic cells (21.4+/- 5.6) in the antisense ODN group (200x ) were less than that of the other three groups (61.6+/- 19.7, 56.5+/- 16.3, 52.2+/- 12.5 respectively), (P< 0.01).

CONCLUSIONThe expression of DAT can be inhibited effectively by the antisense ODN, and the response of the rats to the MPTP was reduced upon DAT inhibition.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine ; pharmacology ; Animals ; Apomorphine ; pharmacology ; Dopamine Plasma Membrane Transport Proteins ; genetics ; physiology ; Immunohistochemistry ; Male ; Oligonucleotides, Antisense ; genetics ; Rats ; Rats, Sprague-Dawley

AIMTo investigate a possible potentiation effect of apomorphine (APO) on sildenafil-induced penile erection in the conscious rabbit.

METHODSErection of male New Zealand White rabbits (3.5 - 4.0 kg, n=12) was assessed by measuring the length of the uncovered penile mucosa and the duration of erection before and after intravenous administration of agents. After injection of APO (0, 0.05, 0.1 and 0.4 mg/kg), sildenafil was administered intravenously in a dose-response manner (0.5, 1 and 5 mg/kg). In additional experiments, the effect of increasing doses of sildenafil in combination with APO on systemic blood pressure was evaluated.

RESULTSSystemic administration of sildenafil induced a dose-dependent increase in the penile length. Intravenous injection of APO alone did not produce any change in the penile length, while significantly enhanced the penile erection induced by sildenafil. The co-administration of 0.1 mg/kg of APO and 1 mg/kg of sildenafil was found to be the most effective combination in producing penile erection. Intravenous administration of sildenafil caused a concentration-dependent decrease in systemic blood pressure, but no additional decrease was observed with co-administration of APO.

CONCLUSIONAPO enhances the penile erection induced by sildenafil in the conscious rabbit without causing an additional decrease in blood pressure.

Animals ; Apomorphine ; pharmacology ; Blood Pressure ; drug effects ; Consciousness ; Drug Synergism ; Male ; Penile Erection ; drug effects ; physiology ; Piperazines ; pharmacology ; Purines ; Rabbits ; Sildenafil Citrate ; Sulfones

In the recent few years, especially since the introduction of phosphodiesterase-5 inhibitor, sildenafil, most researchers have focused their researches on biochemistry and physiology of erectile function. New progress has been made made in basic and clinic researches on pharmacotherapy for ED. In this article, the putative molecular or cellular mechanism of actions of the available centrally and peripherally acting drugs are reviewed, providing details about the current and most explosive area of drug research and development in erectile dysfunction.
Animals ; Apomorphine ; pharmacology ; therapeutic use ; Erectile Dysfunction ; drug therapy ; Humans ; Male ; Phosphodiesterase Inhibitors ; pharmacology ; therapeutic use ; Piperazines ; pharmacology ; therapeutic use ; Purines ; pharmacology ; therapeutic use ; Rats ; Sildenafil Citrate ; Sulfones ; pharmacology ; therapeutic use ; Yohimbine ; pharmacology ; therapeutic use

Intermittent administrations of dopaminergic agents in hemiparkinsonian rat enhances the behavioral response to subsequent administration of the drugs. This phenomenon is known as "priming" and thought as comparable to drug-induced dyskinesia in patients with Parkinson's disease. We investigated the behavioral and electrophysiological changes in 6-hydroxydopamine (6-OHDA)-lesioned hemiparkinsonian rats after repeated administrations of apomorphine. Administration of apomorphine (0.32 mg/kg, intraperitoneal, i.p.) twice daily for 6 days enhanced the rotation induced by apomorphine from 341 turns/hour at the beginning to 755 turns/hr at the end. At the same time, the response to selective D2 agonist quinpirole (0.26 mg/kg, i.p.) was also enhanced from 203 to 555 turns/hr. Extracellular single unit recording revealed no significant difference in the basal firing rates of substantia nigra pars reticulata (SNr) neurons between the ipsilateral and contralateral side of the 6-OHDA lesion regardless of the repeated administrations of apomorphine. In SNr of the lesion side, the units with burst firing pattern were found more frequently after repeated administrations of apomorphine and the suppressive effect of quinpirole on the firing rate was enhanced. These findings suggest that the increased percentage of the burst units is the important electrophysiological change in the development of enhanced response to selective D2 agonist.
Animal ; Apomorphine/*pharmacology ; Dopamine Agonists/*pharmacology ; MPTP Poisoning/physiopathology ; Male ; Oxidopamine/toxicity ; Parkinsonian Disorders/*physiopathology ; Quinpirole/pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptors, Dopamine D2/*drug effects ; Substantia Nigra/*drug effects/physiology

OBJECTIVETo explore the effects of growth hormone( GH) supplementation on erectile function and expression of nNOS in the intracavernosal nerves in aging rats.

METHODSTwenty male Sprague-Dawley rats aged 18 months were randomly divided into Groups A and B, and ten 2-month-old male Sprague-Dawley rats included in Group C. 1 U/(kg x d) GH was given to Group A, and the same volume of saline to Groups B and C. After 8 weeks of treatment, evaluation was made of the erections induced by apomorphine (APO), maximal intracavernous pressure (ICP) induced by intracavernous papaverine injection and expression of nNOS in the intracavernosal nerves by streptavidin-peroxidase immunohistochemical techniques.

RESULTSAfter 8 weeks of treatment, the erection frequency, maximal ICP and expression of nNOS in the intracavernosal nerves of the rats in Groups A and C were significantly higher than those in Group B (P < 0.05 or P < 0.01).

CONCLUSIONGrowth hormone supplementation can improve the erectile function of aging rats, which may be attributed to the increase in the expression of nNOS in the intracavernosal nerves.

Animals ; Apomorphine ; pharmacology ; Growth Hormone ; pharmacology ; Immunohistochemistry ; Male ; Nitric Oxide Synthase Type I ; biosynthesis ; Papaverine ; pharmacology ; Penile Erection ; drug effects ; Penis ; enzymology ; innervation ; Random Allocation ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the expressions of HO-2 and CO in the corpus cavernosum of castrated rats in order to further study the pathogenesis of erectile dysfunction (ED).

METHODSWe randomly divided 72 male SD rats into four groups: normal control, sham operation, castration, and castration + ZnPP. We detected intracavernous pressure (ICP) and penile erection in the basic condition and after apomorphine (APO) induction, determined the expression of the HO-2 protein in the corpus cavernosum by laser scanning confocal microscopy, and measured the level of CO by spectrophotometry during different periods of penile erection.

RESULTSThe ICP in the basic condition and that after APO induction and the rate of penile erection were decreased significantly in the castration group ([11.68 ± 0.69] mmHg, [54.81 ± 3.86] mmHg, and 33.3%) and the castration + ZnPP group ([11.20 ± 0.71] mmHg, [41.17 ± 5.41] mmHg, and 22.2%) as compared with the normal control ([22.83 ± 2.66] mmHg, [66.92 ± 7.77] mm-Hg, and 100%) and the sham operation group ([23.35 ±2.22] mmHg, [70.43 ?7. 22] mmHg, and 100%) (all P <0. 01). After APO induction, ICP in the castration + ZnPP group was remarkably reduced in comparison with that in the castration group (P < 0.01), and so was the expression of the HO-2 protein before and during penile erection in the castration (445.4 ± 23.7 and 847.4 ± 35.0) and the castration + ZnPP group (390.1 ± 29.7 and 526.0 ± 52.5) compared with the normal control (512.7 ±57.4 and 1145.2 ± 89.8) and the sham operation group (583.7 ± 8.0 and 1016.3 ± 79.8), the expression of the HO-2 protein significantly decreased in the castration group (445.4 ± 23.7 and 847.4 ± 35.0) (P < 0.05 or 0.01), markedly lower in the castration + ZnPP than in the castration group during penile erection (P < 0.01) but with no significant differences among the four groups after it. Before, during and after penile erection, the levels of CO were remarkably decreased in the castration ([20.59 ± 1.01], [32.53 ± 1.26], and [18.71 ± 1.22] x 10(-7) nmol/L) and the castration +ZnPP group ([12.52 ± 1.05], [21.90 ± 1.02], and [16.56 ± 0.55] x 10(-7) nmol/L) as compared with the normal control ([26.76 ± 1.41], [48.25 ± 1.01], and [27.10 ± 1.58 ] x 10(-7) nmol/L) and the sham operation group ([25.41 ± 2.09], [ 47.90 ± 1.22], and [25.67 ± 1.20] x 10(-7) nmol/L) (P < 0.05 or 0.01), significantly lower in the castration + ZnPP than in the castration group during penile erection (P < 0.01).

CONCLUSIONDecreased expressions of HO-2 and CO may correlate with erectile dysfunction in castrated rats.

Animals ; Apomorphine ; pharmacology ; Carbon Monoxide ; metabolism ; Dopamine Agonists ; pharmacology ; Erectile Dysfunction ; etiology ; Humans ; Male ; Molecular Chaperones ; metabolism ; Orchiectomy ; Penile Erection ; drug effects ; Penis ; drug effects ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the effects of growth hormone (GH) on the erectile function and the number of neuronal nitric oxide synthase (nNOS) -containing nerve fibers in the penis of aged rats.

METHODSTwenty-four aged male SD rats (18 months) were randomized into 2 groups: GH intervention group and control group. After four and eight weeks, a half of each group were selected and tested for erectile function after apomorphine (APO) injection and then sacrificed for the detection of nNOS-containing nerve fibers in the penis by streptavidin-peroxidase conjugated method (SP method).

RESULTSAfter four weeks, the erectile function and the number of nNOS-containing nerve fibers showed no significant difference between the GH intervention group and the control group (P > 0.05). After eight weeks, the erection frequency was significantly different (P < 0.05) between the two groups, while the erection rate was not. The number of nNOS-containing nerve fibers in the GH intervention group was significantly larger than that in the control group (P < 0.01).

CONCLUSIONGH enhances the regeneration of nNOS-containing nerve fibers in the penis and improves the erectile function of the aged rat.

Animals ; Apomorphine ; pharmacology ; Human Growth Hormone ; pharmacology ; Immunohistochemistry ; Male ; Nerve Fibers ; enzymology ; physiology ; Nerve Regeneration ; drug effects ; Nitric Oxide Synthase Type I ; analysis ; Penile Erection ; drug effects ; Penis ; enzymology ; innervation ; Random Allocation ; Rats ; Rats, Sprague-Dawley

AIMTo explore the mechanism of chronic renal failure (CRF)-related erectile dysfunction (ED).

METHODSCRF experimental models were established by 5/6 nephrectomy from male Sprague-Dawley rats. Both the rats from the control group (NCRF group, n=6) and the experimental group (CRF group, n=30) were injected with a low dose (80 microg/kg) of apomorphine in the 12th week after resection surgery to measure corresponding penile erections. Western blot method was thereafter conducted to measure the expression of connexin 43 (CX43) in the rat corpus cavernosum in the 12th week after the resection surgery.

RESULTSThere was one death in the NCRF group and five in the CRF group. The penile erection ratio of the CRF group was 28% (7/25), whereas that of the NCRF group was 100% (5/5), which presents a significant difference between the two groups (P < 0.05). In terms of penile erection frequency, the average of the CRF group was 1.0 +/- 0.0, which was significantly different from that of the NCRF group (2.2 +/- 0.8) (P < 0.05). As for the expression of CX43 in the rat corpus cavernosum, a notable difference existed between the CRF group (0.21 +/- 0.07) and the NCRF group (0.53 +/- 0.27) (P < 0.01).

CONCLUSIONCRF significantly reduces the erectile function of rats. A close correlation exists between the expression of CX43 in rats' corpus cavernosum and CRF-related ED.

Animals ; Apomorphine ; pharmacology ; Blotting, Western ; Connexin 43 ; genetics ; Disease Models, Animal ; Erectile Dysfunction ; genetics ; Gene Expression ; Kidney Failure, Chronic ; complications ; Male ; Penile Erection ; drug effects ; physiology ; Penis ; enzymology ; Rats ; Rats, Sprague-Dawley