[The relationship between fragmented QRS complex and coronary collateral circulation in patients with chronic total occlusion lesion without prior myocardial infarction].

Objective: To explore the relationship between fragmented QRS complex(fQRS) and coronary collateral circulation(CCC) in patients with chronic total occlusion(CTO)lesion without prior myocardial infarction. Methods: This retrospective study analyzed 238 consecutive patients with CTO lesion in one of the major coronary arteries from May 2014 to October 2015 in our department. Patients were divided into poor CCC group (grade 0 and 1, 58 cases) and good CCC group(grade 2 and 3, 180 cases) based on Rentrop's classification of CCC. The fQRS was defined as the presence of an additional R wave or notching of R or S wave or the presence of fragmentation in two contiguous electrocardiogram leads corresponding to a major coronary artery territory. Multivariate logistic regression was used to analyze the relationship between CCC and fQRS on electrocardiogram. Results: Compared with good CCC group, patients in poor CCC group had older age((65.2±8.9)years old vs. (60.3±10.1) years old, P=0.03), higher plasma glucose ((7.22±3.00) mmol/L vs.(6.31±1.83)mmol/L, P=0.04), and lower left ventricular ejection fraction ((45.2±11.4)% vs. (51.2±13.5)%, P=0.02). None of patients had Rentrop grade 0, the presence of fQRS on ECG in patients with Rentrop grade 1, grade 2, and grade 3 CCC was 69.0% (40/58), 48.6% (35/72) , and 19.4% (21/108), respectively (P<0.01). The presence of fQRS were higher in poor CCC group than in good CCC group (69.0%(40/58)vs. 31.1%(56/180), P<0.01), and number of leads with fQRS were higher in poor CCC group than in good CCC group (3(0, 4)vs.0(0, 3), P<0.01). Multivariate logistic regression analysis demonstrated that poor CCC growth in patients with CTO lesion without prior myocardial infarction was independently related to the presence of fQRS (OR=3.659, 95%CI 1.619-8.217, P<0.01). Conclusion: Poor CCC in patients with CTO lesion without prior myocardial infarction is independently related to the presence of fQRS on electrocardiogram.

[Effects of tibial second toe free flap bridged with blood flow and nerve in the treatment of severe flexion contracture of the proximal interphalangeal joint].

Objective: To investigate the effects of tibial second toe free flap bridged with blood flow and nerve in the treatment of severe flexion contracture of the proximal interphalangeal joint. Methods: A retrospective observational study was conducted. From March 2013 to October 2019, 9 patients with severe flexion contracture (type Ⅲ) of the proximal interphalangeal joint after trauma operation, conforming to the inclusion criteria, were hospitalized in Suzhou Ruihua Orthopaedic Hospital, including 5 males and 4 females, aged from 17 to 62 years. After the contracture tissue affecting the extension of the proximal interphalangeal joint was cut off, and the scar tissue was resected, the size of the volar wound near the proximal interphalangeal joint in extended position was 2.0 cm×1.0 cm-2.5 cm×1.5 cm, with the length of proper digital artery and nerve defect being 1.0-1.5 cm. A free flap of the same size as the wound was cut from the tibial side of the second toe and transplanted to repair the wound, and the defective proper digital artery and nerve was repaired by bridging with the tibial proper plantar digital artery and nerve of about 1.5 cm in length. The full-thickness skin graft was taken from the proximal tibial side of the lower leg to repair the wound at flap donor site. The wound at skin graft donor site was sutured directly. The survival of flap and skin graft was observed after operation. The patients were followed up, and at the last follow-up, the recovery of the affected finger and the second toe, including the donor and recipient areas were observed, the two-point discrimination distances of the flap repaired site and the pulp of the affected finger were observed and measured at the same time, the blood flow patency of bridged vessel of the affected finger was examined by Allen test, and the function of the proximal interphalangeal joint of the affected finger was evaluated according to Chinese Medical Association's standard for the range of motion of proximal interphalangeal joint. Results: The flaps and skin grafts survived smoothly after operation. The follow-up after operation lasted for 5 to 22 months, with a mean of 10 months. At the last follow-up, the flap repaired site had good shape, good color and texture, with the two-point discrimination distance being 9-12 mm, and the two-point discrimination distance of the pulp of the affected finger was 6-10 mm; the Allen test results of the affected fingers were all negative (i.e., the bridged vessels had good blood flow patency), with no recurrence of flexion contracture, and the function of the proximal interphalangeal joint was evaluated as excellent; the skin graft area of the second toe was not ruptured but was a little pigmented, and the flexion and extension activities of toe were good. Conclusions: The tibial second toe free flap bridged with blood flow and nerve has reliable therapeutic effect in the treatment of severe flexion contracture of the proximal interphalangeal joint, and the color and texture of the flap repaired area are good. Bridging to repair the severely contracted proper digital artery and nerve is beneficial to improve the blood supply of the finger body and rebuild the sensation.

[Comparative study of the effects between second toe tibial dorsal artery flap and second toe tibial plantar proper artery flap in repairing finger skin and soft tissue defects].

Objective: To compare the effects between second toe tibial dorsal artery flap (2-TDAF) and second toe tibial plantar proper artery flap (2-TPPAF) in repairing finger skin and soft tissue defects. Methods: A retrospective cohort study was conducted. From January 2019 to June 2020, 27 patients with skin and soft tissue defects at the fingertips with area of 1.5 cm×1.2 cm-2.6 cm×1.8 cm after debridement who met the inclusion criteria were admitted to Suzhou Ruihua Orthopaedic Hospital, including 21 males and 6 females, aged 19-59 (37±10) years. According to flap repair methods used in the defective fingers, the patients were divided into 2-TDAF group (12 cases) and 2-TPPAF group (15 cases). The area of 2-TDAF ranged from 1.5 cm×1.2 cm to 2.5 cm×1.6 cm, and the area of 2-TPPAF ranged from 1.7 cm×1.3 cm to 2.6 cm×1.8 cm. Full-thickness skin grafts from the medial side of the ipsilateral leg were grafted to the wounds in donor sites, and the wounds in donor sites of skin grafts were directly sutured. Flap arterial diameter, flap excision time, flap survival situation of patients in 2 weeks after operation, and follow-up time were recorded. At the last follow-up, the two-point discrimination distance of flap graft site, total action motion (TAM) of the finger joints, and wound healing of the flap donor site were recorded; the Vancouver scar scale (VSS) was used to score the scar in donor area of the second toe and the recipient area of fingers; the appearance and self-satisfaction subscales of the Michigan hand outcomes questionnaire (MHQ) were used to evaluate the affected finger. Data were statistically analyzed with independent sample t test or Fisher's exact probability test. Results: The flap artery diameter of patients in 2-TDAF group was 0.35-0.80 (0.56±0.14) mm and the flap cutting time was (14.0±2.7) min, which were significantly shorter than 0.80-1.35 (1.02±0.16) mm and (19.7±3.4) min in 2-TPPAF group (with t values of 7.81 and 4.79, respectively, P<0.01). The flaps of patients in the 2 groups in recipient areas survived well in 2 weeks after operation, and the wounds in donor areas of flaps of patients in the 2 groups healed well at the last follow-up. There was no statistically significant difference in the postoperative follow-up time, and two-point discrimination distance of flap graft site, TAM of the finger joints, VSS score of scar in the second toe donor site and the finger recipient site, and the appearance and self-satisfaction of MHQ scores of the affected finger at the last follow-up (P>0.05). Conclusions: Compared with 2-TPPAF, 2-TDAF has a shallower anatomical layer and shorter time for surgical flap removal, which can preserve the proper arteries and nerves at the base of the toes and reduce the damage to the donor site.

[Clinical effects of extra-long lateral femoral supercharged perforator flaps in repair of foot and ankle wounds].

Objective: To investigate the clinical effects of extra-long lateral femoral supercharged perforator flaps in repair of ankle and foot wounds. Methods: From March 2014 to October 2018, 16 patients with foot and ankle injuries were admitted to our hospital and left large area of wounds on foot and ankle after emergency treatment. There were 13 males and 3 females, with age of 27 to 60 years. The area of the wounds ranged from 14 cm×10 cm to 40 cm×17 cm. The wounds were repaired with extra-long lateral femoral supercharged perforator flaps. The widths of flaps in 8 patients were longer than 8 cm, and the bilobed flaps were designed to repair the wounds. The area of the flaps ranged from 12 cm×5 cm to 40 cm×9 cm. During the operation, 54 perforators were detected, with an average of 3.2 perforators in each flap, and 36 source arteries of perforators were detected. The blood vessel trunk of 15 patients was descending branch of the lateral femoral circumflex artery, and their supercharged mode was anastomosis of the bulky perforator of descending branch of the lateral femoral circumflex artery with the oblique branch of the lateral femoral circumflex artery and/or medial femoral circumflex artery or the descending branch of superficial illiac circumflex artery. The blood vessel trunk of 1 patient was oblique branch of the lateral femoral circumflex artery, and the supercharged mode of the patient was anastomosis of the oblique branch of the lateral femoral circumflex artery with the bulky perforator of the descending branch of the lateral femoral circumflex artery. The wounds were covered with the flaps after supercharged blood vessel anastomosis, and blood vessels in the donor sites were anastomosed with those in the recipient sites. The donor site was sutured directly. The survival of the flap after the operation and healing time of the wound, and the flap condition, the two-point discrimination distance of flap in patients who were reconstructed with sensation, the recovery of the ankle function, and the appearance of the donor site during follow-up were recorded. Results: A total of 17 flaps in 16 patients were designed, including 8 bilobed flaps and 9 non-lobulated flaps. Sixteen flaps in 15 patients survived. Vascular crisis occurred in the flap of one patient, and the flap survived when the vascular crisis was relieved by the second operation. The healing time of foot and ankle wounds ranged from 12 to 90 days. All the lateral femoral donor sites healed completely. During follow-up of 8 to 48 months, flaps in 2 patients were slightly bloated and were trimmed in 6 months after the operation. The other flaps were with good appearance, soft texture, good elasticity, and no rupture or ulceration. The two-point discrimination distances of flaps ranged from 7 to 16 mm in 8 patients who were reconstructed with sensation, and the other flaps recovered protective sensation. The flexion and extension function of ankle joint recovered well, and the walking function was not affected significantly. All donor sites formed linear scar, with no deep tissue infection such as osteomyelitis. Conclusions: The application of extra-long lateral femoral supercharged perforator flaps to repair the large area of wounds in foot and ankle can significantly reduce damage to donor sites and has advantages of rich blood supply and good safety, thus it has satisfactory clinical effects.

[Multiple free homologous superficial peroneal artery perforator flaps of crus for repair of multiple hand wounds].

Objective: To explore the effects of multiple free homologous superficial peroneal artery perforator flaps of crus for repair of multiple hand wounds. Methods: From November 2017 to December 2018, eight cases with eighteen hand wounds were hospitalized in our unit. Among them, wounds were distributed in the forefinger and middle finger in four cases, wounds were distributed in the middle finger and ring finger in two cases, wounds were distributed in the forefinger, middle finger, and ring finger in one case, and wounds were distributed in the middle finger, ring finger, and little finger in one case. The area of skin defect ranged from 1.5 cm×0.8 cm to 4.0 cm×3.0 cm. There were 4 males and 4 females, aged 34-62 years. Wounds of six cases were repaired by two free superficial peroneal artery perforator flaps from homolateral crus, and those of two cases were repaired by three free superficial peroneal artery perforator flaps from homolateral crus. Superficial peroneal artery and its accompanying vein of flap were anastomosed by end to end with digital artery and palmar or dorsal subcutaneous vein of recipient site during the operation. The area of flap ranged from 2.5 cm×1.2 cm to 5.0 cm×4.0 cm. No nerve was harvested during the operation, and donor site was sutured directly. The survival of the flaps and the healing of donor sites were recorded. During follow-up, the recovery of donor and recipient sites was observed. Results: All flaps survived well, donor site healed well. No vascular crisis occurred. Follow-up for 4 to 12 months showed that the appearance of flap was satisfactory with good color, texture, elasticity, and function. Protective sensation of recipient site was recovered. Five months after operation, flap of finger pulp in one case was swollen slightly with two-points discrimination of 10 mm, which received the thinning surgery. Obvious scar formation was not observed in donor site of crus. The appearance of the donor site was good without functional damage. Conclusions: The application of multiple free homologous superficial peroneal artery perforator flaps of crus to repair the multiple hand wounds has advantages of easy acquisition, easy operation, little effect on donor sites, and satisfactory clinical effects.

Involvement of receptor reserve in D1 agonistic action of (-)-stepholidine in lesioned rats.

(-)-Stepholidine (SPD) is a natural product. Previous studies had demonstrated that SPD displayed D1 agonism in unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rats and D1 antagonism in reserpinized rats and normal rats. The aim of the present study was to explain this peculiar pharmacological action based on behavioral and biochemical experiments. In the unilaterally 6-OHDA-lesioned rats, SPD (4 mg/kg, s.c.) induced contralateral rotation as did apomorphine (APO), but the rotation response to SPD was 60% lower than that to APO (0.5 mg/kg, i.p.). Coadministration with APO (0.5 mg/kg, i.p.) and SPD (0.5 to 10 mg/kg, s.c.) produced a biphasic action curve. At low doses (0.5 or 1 mg/kg), SPD potentiated APO action; at high doses (4 or 10 mg/kg), however, SPD suppressed APO. In striatal homogenate of the unilaterally lesioned rats, SPD stimulated cyclic AMP (cAMP) formation and produced a maximal response comparable to that of dopamine (DA) in the denervated striatum, but 70% lower than that of DA in the intact striatum. Coadministration of 10 microM DA with various concentrations of SPD yielded different results, with a biphasic response in the intact side and a synergistic effect in the denervated side. Furthermore, based on the determination of receptor-mediated cAMP formation, the D1 receptor reserve was analyzed in both denervated and intact striatum by using the DA receptor inactivator N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ). The results showed that following EEDQ administration, the receptor density [revealed by [3H]R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-be nzazepine ([3H]SCH-23390) binding] and the agonist-stimulated adenylate cyclase (AC) activity (revealed by cAMP formation) were reduced concurrently. In the intact striatum, the reduction in SPD-stimulated AC activity paralleled the receptor loss, indicating the absence of receptor reserve, while in the denervated striatum the reduction in AC activity was less than the receptor loss, indicating a significant level of receptor reserve (estimated 16.4%). By comparison, receptor reserve for DA was 45.7 and 25.3% in the denervated and intact striatum, respectively, representing an 80% increase of receptor reserve. In conclusion, SPD is a D1 partial agonist, and receptor reserve permits SPD to display its D1 agonistic action in the unilaterally 6-OHDA-lesioned rats.

GTP regulation of (-)-stepholidine binding to R(H) of D1 dopamine receptors in calf striatum.

(-)-Stepholidine (SPD) exhibits antagonist effects on normosensitive dopamine (DA) receptors, but it has an agonist action on rotation in unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rats. The present work endeavors to further elucidate the mechanism of its agonist action on D1 receptors. [3H]R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-be nzazepine ([3H]SCH-23390) and [3H]spiperone were used, respectively, as radioligands in D1 and D2 DA receptor binding assays in calf striatal membranes. Experimental data were analyzed by a non-linear regression computer program, GraphPAD InPlot 3.15. The competition curves were fitted first by a single-site equation and then by a two-site equation. The results showed that both apomorphine (APO) and SPD competitively inhibited [3H]SCH-23390 binding. Their competition curves fitted best to the two-site equation (P < 0.05) with a high-affinity site (R(H)) and a low-affinity site (R(L)) to DA receptors. The K(H) and K(L) values (nM) were 2.7 +/- 0.45 and 378 +/- 62 for APO, and 3.9 +/- 2.2 and 126 +/- 25 for SPD, respectively. In contrast, the competition curve of SCH-23390, a selective D1 DA receptor antagonist, fitted best to a single-site model with a Ki value of 1.7 +/- 0.5 nM. The R(H) of APO or SPD could be decreased by the addition of 450 microM GTP. In the [3H]spiperone binding test, the APO curve was modeled best by the two-site equation, while the SPD curve fitted best to a single-site model. In the rotational behavior test, APO induced 441 +/- 20 turns/30 min in the 6-OHDA-lesioned rats, and SPD induced 310 +/- 42 turns/30 min, while SCH-23390 antagonized the SPD-induced rotation but did not induce rotational behavior. These results suggest that SPD possesses agonist actions on D1 but antagonist effects on D2 DA receptors.

Effect of l-tetrahydropalmatine on dopamine release and metabolism in the rat striatum.

In vivo voltammetric measurements of striatal extracellular DOPAC concentrations and of striatal DA release in combination with post-mortem analysis of striatal catechols were performed in the rat to study the effects on the nigro-striatal neurons of a Chinese neuroleptic, l-tetrahydropalmatine (l-THP), which is known to block post-synaptic dopaminergic receptors. l-THP injected at doses that cause sedation in rats and mice (5-10 mg/kg) induced a marked increase in post-mortem DOPAC levels (+250%), while no significant effect was observed on postmortem DA levels. The extracellular DOPAC concentration was increased to 155 +/- 9% of the control value after l-THP administration (1 mg/kg, IP). Further, an injection of l-THP (1 mg/kg, IP) induced an increase in extracellular DA concentration (220% of the basal value), reversed the decrease in extracellular DA concentration induced by apomorphine (0.05 mg/kg, SC) and enhanced the effects of the electrical stimulation of the nigro-striatal pathway. These results confirm that l-THP acts on the nigro-striatal neurons as a dopaminergic antagonist that can block both post- and presynaptic receptors.

Dual actions of (-)-stepholidine on dopamine receptor subtypes after substantia nigra lesion.

1. It was found that the contralateral rotation challenged by (-)-SPD (4 mg/kg, ip) in 6-OHDA-lesioned rats had a gradually progressive process with long latent period and a maximal response on 63 days after lesion. This steady contralateral rotation was preferably antagonized by D-1 antagonist SCH23390 than D-2 antagonists. During its latent period (-)-SPD exhibited the antagonistic effect to APO, while during its period of full response (-)-SPD could potentiate the APO-induced rotation. 2. In the rats lesioned with kainic acid plus 6-OHDA to destroy the SNC and SNR, (-)-SPD and SKF-38393 challenged neither contralateral nor ipsilateral rotation, while APO still induced the rotation but towards ipsilateral side, just opposite to that in 6-OHDA-lesioned rats. In this case, (-)-SPD antagonized the response to APO as did SCH 23390. 3. These evidences suggest that the agonistic action of (-)-SPD is resulted from D-1 receptor subtype at the SNR under supersensitive functional state. The fact that SNR lesion could completely eliminate the agonistic action of (-)-SPD further indicate that the D-1 receptors in the ipsilateral SNR may be the sites of action of (-)-SPD. The dual actions of (-)-SPD are dependent upon the supersensitivity of D-1 receptor subtypes which render the antagonistic action to convert into the agonistic.

Tetrahydroberberine blocks membrane K+ channels underlying its inhibition of intracellular message-mediated outward currents in acutely dissociated CA1 neurons from rat hippocampus.

In the patch-clamp perforated whole-cell recording mode, tetrahydroberberine (THB), a novel dopamine (DA) receptor antagonist, inhibits not only DA-induced outward K+ currents, but also acetylcholine-, caffeine- or strychnine-induced outward current. However, THB does not affect either GABA- or glycine-induced Cl- currents, or non-NMDA receptor agonist-induced cation currents. As expected for a K+ channel blocker, THB evokes a downward current deflection accompanied by a decrease of conductance. It is concluded that the direct blockade of membrane K+ channels by THB underlies its inhibition of intracellular message-mediated outward currents.

Repeated reserpine treatment alters firing pattern and responses of substantia nigral dopamine neurons.

Repeated reserpine treatment (1 mg/kg x 6 days) increased the number of spontaneously active substantia nigra pars compacta (SNC) dopamine (DA) cells and altered the firing pattern to a more irregular one in locally anesthetized rats. The selective DA D1 receptor agonist, SKF 38393, although having little effect on SNC DA cells in normal rats, profoundly inhibited the firing rate of SNC DA cells in reserpinized rats. On the contrary, the DA D2 receptor agonist, N-0437, significantly inhibited the firing rate of SNC DA cells in control rats, however, the inhibition was not significantly altered by reserpine. The inhibitory effect of the mixed DA receptor agonist, apomorphine, was significantly enhanced after reserpine treatment. In addition, the inhibition of SNC DA cell firing produced by D1 and D2 receptor agonists in reserpinized rats was reversed only by their own subtype antagonists. These results suggest that repeated reserpine treatment renders SNC DA cells responsive to D1 receptor stimulation, and that D1 receptors play a more important role than D2 receptors in the supersensitivity of SNC DA cells induced by repeated reserpine treatment. The results also indicate that D1 and D2 receptor agonists inhibit SNC DA cell firing separately and synergically in reserpinized rats.

Tetrahydroberberine inhibits acetylcholine-induced K+ current in acutely dissociated rat hippocampal CA1 pyramidal neurons.

The effects of a novel chemical type of dopamine receptor antagonist, the tetrahydroprotoberberine analogs (THPBs), on acetylcholine (ACh)-induced current were studied in freshly dissociated pyramidal neurons from rat hippocampal CA1 area using the nystatin perforated patch-clamp recording technique. Under voltage clamp conditions, the ACh-induced outward current (IACh) is sensitive to the muscarinic receptor antagonist, atropine and the K+ channel blocker, TEA. The reversal potential of IACh (-84.1 +/- 0.8 mV) is close to the K+ equilibrium potential, indicating that the IACh is mediated by a muscarinic receptor, and is carried mainly by K+. Tetrahydroberberine (THB) markedly reduced the IACh while its chemical analogs, l-stepholidine (l-SPD) or l-tetrahydropalmatine (l-THP), had little effect on the IACh. The half-maximal inhibitory concentration (IC50) of THB was 1.3 x 10(-5) M for a 10(-5) M ACh-induced IACh. THB suppressed the maximum of the ACh concentration-response curve without shifting the Hill coefficient, indicating a non-competitive inhibition. It is concluded that THB non-competitively inhibits the ACh-induced K+ current in a concentration-dependent manner, and that this inhibitory effect provides further evidence that THB plays its pharmacological roles in the central nervous system by effects other than through blockade of dopamine receptors.

Tetrahydroberberine suppresses dopamine-induced potassium current in acutely dissociated CA1 pyramidal neurons from rat hippocampus.

Effects of tetrahydroberberine (THB) on dopamine (DA)-induced response have been investigated in single pyramidal neurons freshly dissociated from CA1 area of the hippocampus using the nystatin perforated patch-clamp, whole-cell recording technique under voltage-clamp configuration. At a holding potential (VH) of -20mV, DA-induced responses included a transient outward current, a slow inward current and a combination of the two. The outward current had a reversal potential of -83.5 +/- 8.0 mV which was close to K+ equilibrium potential and was sensitive to TEA, suggesting that this outward current was carried by K+. Application of THB reversibly suppressed three type responses induced by DA with different degrees of inhibitory ratio. THB inhibited the DA-induced outward current in a concentration-dependent manner with an IC50 of 13 microM. The maximal value of the concentration-response curve for DA-induced outward current was suppressed by THB, suggesting a non-competitive inhibition. The results support the hypothesis that THB acts as a novel dopaminergic system antagonist. Furthermore, THB inhibits the DA-induced K+ current non-competitively in single dissociated cells, implying that THB may exhibit other pharmacological action on the central nervous system.

D1/D2 dopamine receptor interaction in membrane abolished by 6-hydroxydopamine lesion.

D1/D2 interaction in rat striatum was investigated by examining the effect of the D2 antagonist spiperone on the binding of [3H]SCH23390 to D1 dopamine (DA) receptors. In the presence of endogenous DA, spiperone blocked D2 receptors, then caused the increase of the binding of [3H]SCH23390 in rat striatal homogenate. After the 6-hydroxydopamine (6-OHDA) lesion, the increase was not found even if in the addition of exogenous DA. The results suggest that the D2 antagonist can modify the interaction between endogenous DA and D1 receptors labeled with [3H]SCH23390, while 6-OHDA lesion may change the state of D1/D2 interaction operating at the receptor level.

Enhanced stereotypic behavior by chronic treatment with bromocriptine accompanies increase of D-1 receptor binding.

Different effects of chronic treatment with bromocriptine (BRO) on D-1 and D-2 receptors in the rat were studied through behavioral observation and DA receptor binding assays. Chronic BRO led to enhancement of stereotypy to apomorphine (APO), at the same time it increased the density of D-1 receptor binding by 43% and decreased that of D-2 receptor binding by 21%. Our data suggest that BRO has different effects on D-1 and D-2 receptors and the behavioral hypersensitivity caused by BRO may be relevant to the proliferation of D-1 receptor.

(-)-Stepholidine acts as a D1 partial agonist on firing activity of substantia nigra pars reticulata neurons in 6-hydroxydopamine-lesioned rats.

(-)-Stepholidine (SPD), a novel dopamine (DA) D1 and/or D2 receptor antagonist in normosensitive animals, shows agonistic effects on D1 receptors in rotational behavior of 6-hydroxydopamine (6-OHDA)-lesioned rats. To further characterize the pharmacological properties of SPD, we investigated the effects of SPD on firing activity of substantia nigra pars reticulata (SNR) neurons in different sensitive models. In control rats, the selective D1 agonist SKF38393 (4 mg/kg, i.v.) induced inconsistent changes (i.e. increase, decrease or no change) in firing of SNR neurons. These effects were completely antagonized by SPD (i.v.), regardless of the changes induced by SKF38393. SPD (4 mg/kg), per se, increased firing by 30.9 +/- 14.4%. In reserpinized rats, SKF38393 also induced SPD-reversible inconsistent changes as in control rats. Nevertheless, SPD per se produced no alteration in firing of SNR neurons. In 6-OHDA-lesioned rats, 5/6 SNR neurons were inhibited by SKF38393. The inhibition was completely abolished by Sch23390, a selective D1 antagonist (0.5-2 mg/kg), but partially reversed by SPD (1-16 mg/kg). Moreover, SPD (4 mg/kg) itself caused SNR increased or decreased neuron firing, and these effects were completely reversed by Sch23390 (0.5-2 mg/kg) in 8/12 neurons recorded. These results suggest that SPD acts as a partial agonist to D1 receptors in 6-OHDA-lesioned rats, but as an antagonist to D1 receptors in normal and reserpinized rats.

Involvement of dopamine D1 and D2 receptors in Fos immunoreactivity induced by stepholidine in both intact and denervated striatum of lesioned rats.

Stepholidine (SPD), a natural product, has been demonstrated in previous studies as a D1 agonist and D2 antagonist. In this work SPD-induced Fos immunoreactivity was examined. In the normal rats, Fos was induced in the striatum by SPD (1-20 mg/kg, i.p.) dose-dependently. The distribution of Fos-positive cells induced by SPD showed a rostral-caudal decline, matching the distribution of D2 dopamine receptors. The Fos-positive cells were mainly found in striatal neurons retrogradely labeled with horseradish peroxidase (HRP) from GP but not from SN, and could be abolished by the pretreatment of a D2 agonist LY171555 (2 mg/kg, i.p.), suggesting that the Fos expression in normal rats was due to the D2 antagonistic action of SPD. In the unilateral 6-hydroxydopamine-lesioned rats, SPD (4 mg/kg, i.p.) induced Fos expression in intact and denervated side of the striatum with different characteristics. Similar to that of normal rats, the Fos expression in intact side possessed the rostral-caudal gradient and could be abolished by the pretreatment of LY171555. However, in the denervated side, the Fos positive cells were widely distributed, and mainly found in striatal neurons retrogradely labeled from SN but not from GP. Furthermore, this expression was prevented by the pretreatment of SCH23390 (0.2 mg/kg, i.p.) but not LY171555, suggesting that the Fos expression in denervated side was due to the D1 agonistic action of SPD. Therefore, we concluded that the Fos expression induced by SPD in intact and denervated striatum was mediated via D2 and D1 receptor respectively, supporting the previous standpoint that SPD possesses the dual action, i.e antagonist to D2 and agonist to D1 receptors. Furthermore, it is suggested that the contralateral turning behavior induced by SPD may result from the D1-mediated excitation of striatonigral neurons of the denervated side of the lesioned rats.

Comparison of (-)-stepholidine and D1 or D2 agonists on unit firing of globus pallidus in 6-hydroxydopamine-lesioned rats.

(-)-Stepholidine(SPD), isolated from the Chinese herb Stephania, is demonstrated to be a DA antagonist, but it also shows D1 agonistic action on rotational behavior in unilateral 6-hydroxydopamine (6-OHDA) lesioned rats. The present study further ascertains its D1 agonistic property on firing activity of globus pallidus (GP) in control and 6-OHDA-lesioned rats. In the control rats, the firing activities of the GP neurons elicited by DA agonists (i.v.), such as apomorphine (D1/D2), SKF38393 (D1), and LY171555 (D2), were readily reversed by SPD (4 mg/kg, i.v.); but SPD, per se, induced variable alterations. In the 6-OHDA-lesioned rats, apomorphine, SKF38393 and LY171555 displayed the marked inhibition as well as excitation on the unit firing. The individual firing variations (87.1+/-17.8, 55.1+/-15.7 and 62.1+/-16.7%, respectively) were much larger than those in the control group, and were completely abolished by SPD (2 mg/kg). However, SPD also showed D1 partial agonistic action on the GP neuron firing. Moreover, the pre-blockade of D2 receptors with spiperone (0.5 mg/kg, i.v.), SPD exhibited the D1 agonist action which was reversed by the D1 antagonist SCH23390. These results suggest that SPD has a dual action on the GP neuron firing in the 6-OHDA-lesioned rats, i.e., antagonist to D2 DA receptors and partial agonist to D1 receptors.

Modulation of medical prefrontal cortical D1 receptors on the excitatory firing activity of nucleus accumbens neurons elicited by (-)-Stepholidine.

(-)-Stepholidine (SPD), with D1 agonistic action, elicited an excitatory firing activity of nucleus accumbens (NAc) neurons by intravenous administration, but this effect was hardly observed by iontophoresis of SPD into the NAc. The present study intends to determine whether D1 receptors in the medial prefrontal cortex (mPFC) are involved in the action of SPD on the firing activity of NAc neurons in the chloral hydrate-anesthetized male rats. The results showed that the intra-mPFC microinjected SCH-23390 (D1 antagonist, 30 mM), but not the D2 antagonist spiperone (30 mM), significantly attenuated the enhanced firing activity induced by intravenous injection of SPD (2 mg/kg). Similarly, the excitatory firing of NAc neurons was also exhibited by the microinjection of either SPD or D1 agonist SKF-38393 into the mPFC. The SPD-induced excitatory effect was in a dose-dependent way from 277.8 +/- 51.3% (10 mM) to 1105.4 +/- 283.5% (30 mM) of NAc basal firing, which was completely reversed by SCH-23390 (i.v.). Furthermore, the direct D1 agonistic action of SPD on the mPFC neuron was observed with microiontophoresis. These results indicate that SPD possesses a direct agonistic action on the mPFC D1 receptors, by which it modulates the firing activity of NAc neurons.

Dual actions of (-)-stepholidine on the dopamine receptor-mediated adenylate cyclase activity in rat corpus striatum.

(-)-Stepholidine (SPD) is an antagonist of normosensitive dopamine (DA) receptors, but it exhibits D1 agonistic action on rotational behaviour in rats with unilateral 6-hydroxydopamine (6-OHDA) lesions of the substantia nigra pars compacta (SNC). In the present study, agonistic and antagonistic effects of SPD on the DA receptor-mediated synaptosomal adenylate cyclase (AC) activity in rat striatum were investigated. After blockade of D2 receptors, SPD augmented AC activity dose-dependently. The EC50 value was 41.1 +/- 8.6 micromol/L. At the concentration of 10 micromol/L, SPD increased cAMP formation from a basal level (50.8 +/- 10.3 pmol/mg protein/min) to 133.7 +/- 31.8 pmol/mg protein/min. The SPD-induced stimulation of AC activity was almost completely reversed by 10 micromol/L Sch23390. These results indicate that SPD possesses an agonistic action on the D1 receptor. Forskolin-stimulated adenylate cyclase (FSAC) activity was used as a model to elucidate the effect of SPD on D2 receptors. The results indicate that DA inhibited FSAC activity dose-dependently, while SPD partially restored FSAC activity. Taken together, these results support the conclusion that SPD has dual actions on DA receptors that mediate AC activity, i.e., an agonistic action on D1 receptors and an antagonistic action on D2 receptors.