Pharmacokinetic/pharmacodynamic analysis of adjunctive perampanel in subjects with partial-onset seizures.

OBJECTIVES: Explore perampanel pharmacokinetics (PK) in all subjects (aged ≥12 years) vs adolescents (aged ≥12 to ≤17 years) with partial-onset seizures (POS) and identify factors explaining between-subject variability in efficacy using a population PK/pharmacodynamic (PD) analysis. MATERIALS & METHODS: Population PK analysis was performed using nonlinear mixed-effect modeling with data from phase II/III randomized, double-blind, placebo-controlled studies of adjunctive perampanel in POS. Perampanel exposure was predicted for all subjects and adolescents. Population PK/PD analyses were performed using data from phase III studies to explore the relationship between perampanel exposure and 28-day average seizure frequency and responder probability. RESULTS: Pooled perampanel PK data from 1318 subjects were described by a one-compartment disposition model. In the absence of antiepileptic drugs (AEDs) affecting perampanel PK, estimated perampanel apparent clearance (CL/F) was 0.668 L/h (all subjects) and 0.682 L/h (adolescent subjects). Co-administration of carbamazepine and oxcarbazepine/phenytoin reduced perampanel exposure. Gender, Asian race (excluding Japanese or Chinese), and increasing alanine aminotransferase lowered perampanel CL/F, but differences were small and not considered clinically relevant. Adolescent outcomes were similar to the total population. Based on PK/PD data from 1748 subjects, percent reduction in 28-day average seizure frequency from baseline and responder probability increased with increasing perampanel exposure; concomitant CYP3A-inducing AEDs lowered perampanel exposure but did not impact the slope for responder probability. CONCLUSIONS: These results are consistent with previous analyses but expand on these through inclusion of a larger number of patients from different ethnic groups, and demonstrate that outcomes were similar between adults and adolescents.

Forskolin: a specific stimulator of adenylyl cyclase or a diterpene with multiple sites of action?

Forskolin, a naturally occurring diterpene, directly stimulates adenylyl cyclase and has been used extensively to increase cAMP and to elicit cAMP-dependent physiological responses. More recently, forskolin has been shown to inhibit a number of membrane transport proteins and channel proteins through a mechanism that does not involve the production of cAMP. Many of these channel proteins are predicted to have similar topographies in the membrane bilayer and it is tempting to speculate that forskolin may be binding at structurally homologous sites. Kenneth Seamon and colleagues discuss the cAMP-independent effects of forskolin and the structural similarity between forskolin and other physiologically important substances such as hexoses and steroids with respect to potential forskolin binding sites.

A stimulating effect of guanyl nucleotides on the rat-liver soluble cyclic GMP high-affinity phosphodiesterase activity.

The high affinity (low Km) cyclic GMP phosphodiesterase (PDE) is activated by GTP, while the cyclic AMP PDE is not. GTP and its hydrolysis-resistant analogue, guanylylimidodiphosphate (GppNHp), display a half-maximal stimulating effect at almost the same concentration (5 X 10(-6) M). The GTP stimulating effect is not observed when the socalled cyclic GMP low affinity (high Km) PDE is operative. GTP cooperates with the increase of the substrate concentration on removing the IBMX inhibitory effect. The isolation through a classical chromatographic procedure on a DEAE-cellulose column, of a PDE fraction specific for cyclic GMP, results in the loss of the GTP stimulating effect.

Naratriptan is effective and well tolerated in the acute treatment of migraine. Results of a double-blind, placebo-controlled, crossover study. The Naratriptan S2WA3003 Study Group.

The efficacy and tolerability of naratriptan tablets (2.5 mg, 1 mg, and 0.25 mg) compared with placebo in the acute treatment of migraine were evaluated in a randomized, double-blind, four-period crossover study. Five hundred eighty-six assessable patients received naratriptan 2.5 mg, 595 received 1 mg, 591 received 0.25 mg, 602 received placebo. Headache relief (moderate or severe pain reduced to mild or none) 4 hours postdose was reported in 68% of patients after treatment with naratriptan 2.5 mg compared with 57% after 1 mg, 39% after 0.25 mg, and 33% after placebo (p < 0.001 naratriptan 2.5 mg and 1 mg versus placebo and 1 mg and 2.5 mg versus 0.25 mg). Headache relief was maintained 8, 12, and 24 hours postdose with no use of rescue medication or a second dose of study medication by significantly (p < 0.001) greater percentages of patients after treatment with naratriptan 2.5 mg or 1 mg compared with naratriptan 0.25 mg or placebo. Naratriptan was also more effective than placebo in reducing clinical disability and the incidences of nausea, photophobia, and phonophobia. The overall incidence of adverse events and the incidences of specific adverse events did not differ in the naratriptan groups compared with placebo. No clinically relevant changes in ECG, blood pressure, or laboratory findings were reported. These data demonstrate that naratriptan is effective and well tolerated for the acute treatment of migraine. The 2.5-mg dose was associated with superior efficacy, whereas its adverse event profile was similar to that of placebo.

(Aminoalkyl)carbamates of forskolin: intermediates for the synthesis of functionalized derivatives of forskolin with different specificities for adenylyl cyclase and the glucose transporter.

(Aminoalkyl)carbamates of forskolin were synthesized at the 6- and 7-hydroxyl positions of forskolin with the length of the alkyl chain varying from ethyl to heptyl. Two of these derivatives, 7-[[(2-aminoethyl)amino]carbonyl]-7-desacetylforskolin (2) and 6-[[(2-aminoethyl)amino]carbonyl]forskolin (3), were used to synthesize iodinated derivatives of forskolin that bind with high affinity to adenylyl cyclase in bovine brain membranes and the glucose transporter in human erythrocyte membranes, respectively. Hydroxyphenyl derivatives of forskolin were prepared from the (aminoalkyl)carbamates and tested for their ability to bind to adenylyl cyclase in bovine brain membranes and the glucose transporter in human erythrocyte membranes. The 6-derivative (18) of forskolin had a Kd of 9 nM at adenylyl cyclase and was more potent than either the 7-derivatives or the 6-derivatives of 7-desacetylforskolin. The 7-derivatives were more potent at binding to the glucose transporter than forskolin. In contrast, the 6-derivatives had Kd's greater than 100 microM at the glucose transporter. Isothiocyanates and N-bromoacetyl derivatives were synthesized from 2 and 3 as potential alkylating agents for forskolin binding sites. The alkylating agents produced an irreversible loss of forskolin binding to adenylyl cyclase. In contrast, the alkylating agents bound reversibly to the glucose transporter.

One-year tolerability and efficacy of sumatriptan nasal spray in adolescents with migraine: results of a multicenter, open-label study.

OBJECTIVE: The objective of this study was to determine the 1-year tolerability and efficacy of sumatriptan nasal spray (NS) at doses of 5, 10, and 20 mg for the treatment of acute migraine in adolescents. METHODS: This was a prospective, multicenter, open-label, 1-year, multiple-attack study. Adolescents (aged 12-17 years) with a > or =6-month history of migraine with or without aura, 2 to 8 moderate or severe migraines per month, and a typical migraine duration of > or =4 hours were eligible for participation. After initial treatment with sumatriptan 10 mg, the dose could be adjusted down to 5 mg or up to 20 mg at the investigator's discretion to optimize tolerability or efficacy. Patients could treat an unlimited number of moderate or severe migraine attacks, provided there was a 24-hour headache-free period between treated attacks and a 2-hour period between doses of sumatriptan NS. A second dose of sumatriptan NS was available for headache recurrence 2 to 24 hours after initial treatment; no more than 2 doses could be used within a 24-hour period. Adverse events, vital signs, electrocardiographic and physical findings, and laboratory variables were assessed. Headache response (reduction of moderate/severe predose pain to mild/no pain) and pain-free response (reduction of moderate/severe predose pain to no pain) were reported by patients 2 hours after dosing. RESULTS: A total of 437 patients treated > or =1 migraine; 3272 total attacks were treated, with 3675 drug exposures (mean, 1.1 dose/attack). Patients had a mean age of 14.1 years, 91% were white, and 53% were female. Seven patients used the 5-mg dose; meaningful conclusions concerning this dose could not be made. Drug-related adverse events were reported in 33% of attacks with the 10-mg dose and 31% with the 20-mg dose; most were related to taste disturbance. Adverse events did not increase with a second dose or over time. Four percent (16/437) of patients withdrew due to drug-related adverse events. One serious adverse event, a facial-nerve ischemic event (10-mg dose), was considered drug related. No drug-related changes in vital signs or electrocardiographic findings were observed. Headache response 2 hours after dosing was reported by 76% of patients taking the 10-mg dose and 72% of those taking the 20-mg dose. Pain-free response 2 hours after dosing was reported by 43% and 40% of patients in the 10- and 20-mg groups, respectively. CONCLUSIONS: Based on these results, sumatriptan NS at doses of 10 and 20 mg was well tolerated and effective in the 1-year treatment of multiple migraine attacks in adolescents.

Differential identification and localization of adenylyl cyclase and glucose transporter in brain using iodinated derivatives of forskolin.

Two radioiodinated derivatives of forskolin, [125I]6-IHPP-Fsk and [125I]7-IHPP-Fsk, were synthesized as specific ligands for adenylyl cyclase and glucose transporter, respectively. [125I]6-IHPP-Fsk bound to bovine brain homogenates with a Kd of 9 nM and binding was inhibited by forskolin but not 1,9-dideoxyforskolin, cytochalasin B, or D-glucose. [125I]7-IHPP-Fsk bound to bovine brain homogenates at two classes of binding sites with Kd's of 56 nM and 4.7 microM; cytochalasin B and D-glucose inhibited 75% of the high affinity binding while having no effect on the low affinity binding. [125I]6-IHPP-Fsk and [125I]7-IHPP-Fsk were used to localize adenylyl cyclase and glucose transporter in rat brain by receptor autoradiography. The pattern of binding obtained with [125I]6-IHPP-Fsk was similar to that observed using [3H]forskolin to detect adenylyl cyclase. In contrast, the pattern of binding obtained with [125I]7-IHPP-Fsk was similar to that observed by others using [3H]cytochalasin B to detect glucose transporter. These iodinated ligands are selective for adenylyl cyclase and glucose transporter and require significantly shorter exposure times to yield autoradiographs than tritiated ligands.

Development of perampanel in epilepsy.

Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors play a key role in mediating glutamatergic transmission in the cortex. Perampanel (2-[2-oxo-1-phenyl-5-pyridin-2-yl-1,2-dihydropyridin-3-yl] benzonitrile) is a potent, orally active, highly selective, non-competitive AMPA-type glutamate receptor antagonist, identified via a focused discovery program at Eisai Research Laboratories. Development of perampanel as adjunctive therapy for the treatment of partial-onset seizures was planned in keeping with regulatory guidance and guidelines on antiepileptic drug (AED) development. This is the first AED with a specific action on glutamate-mediated excitatory neurotransmission to show evidence of efficacy and tolerability in reducing treatment-refractory partial-onset seizures in Phase III clinical trials. Perampanel (Fycompa(®)) has been approved in the EU and the United States for adjunctive treatment of partial-onset seizures.

Randomized phase III study 306: adjunctive perampanel for refractory partial-onset seizures.

OBJECTIVE: To evaluate the efficacy and safety of perampanel 2, 4, and 8 mg/day added to 1-3 concomitant antiepileptic drugs (AEDs) in patients with uncontrolled partial-onset seizures. METHODS: During this double-blind, placebo-controlled trial, patients with persisting seizures on 1-3 AEDs were randomized to perampanel 2, 4, and 8 mg/day or placebo following a 6-week baseline phase. Perampanel was titrated weekly by 2 mg/day and maintained at the dose achieved for 13 weeks. Primary endpoints were median percent change in seizure frequency and 50% responder rate. Analysis of covariance was performed on all treated patients with any seizure data (recorded in daily diaries) in the double-blind phase. RESULTS: A total of 706 patients were randomized and received trial medication; 623 completed the trial. Median percent change in seizure frequency-the primary efficacy endpoint-was -10.7%, -13.6%, -23.3%, and -30.8% for placebo, perampanel 2, 4, and 8 mg/day, respectively. The difference from placebo was statistically significant for perampanel 4 mg/day (p = 0.0026) and 8 mg/day (p < 0.0001). The corresponding 50% responder rates were 17.9%, 20.6%, 28.5%, and 34.9%. The difference from placebo was statistically significant for perampanel 4 mg/day (p = 0.0132) and 8 mg/day (p = 0.0003). An apparent dose response was suggested for dizziness, which was the most frequent treatment-emergent adverse event. CONCLUSIONS: This trial demonstrated that adjunctive perampanel effectively reduced seizure frequency and possessed a favorable tolerability profile in patients ≥12 years with partial-onset seizures (with or without secondary generalization), with a minimum effective dose of 4 mg/day. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that 4 and 8 mg/day doses of adjunctive perampanel are effective and tolerated in reducing partial-onset seizures.

Irreversible loss of [3H]forskolin binding sites in human platelets by alpha-haloacetyl analogs of forskolin.

The 7-bromoacetyl-7-desacetyl (BrAcFsk) and 7-chloroacetyl-7-desacetyl (CIAcFsk) analogs of forskolin were synthesized as alkylating agents to study the high affinity binding sites for forskolin. BrAcFsk and CIAcFsk activated adenylate cyclase in human platelet membranes with EC50 values of about 20 and 12 microM, respectively. Both analogs increased cyclic AMP in human platelets; however, they were less potent that forskolin. Forskolin inhibited [3H]forskolin binding to human platelet membranes with an IC50 of 20 nM, whereas BrAcFsk and CIAcFsk inhibited [3H] forskolin binding with IC50 values of 0.1 microM. Pretreatment of intact platelets with 10 microM BrAcFsk caused a 90% irreversible loss in [3H]forskolin binding sites, whereas pretreatment with 10 microM CIAcFsk led to a loss of 55% of the binding sites. The loss of binding sites occurred within 5 min for BrAcFsk and within 30 min for CIAcFsk. The time required for the loss of binding sites produced by either alkylating agent was increased by the inclusion of 200 microM forskolin in the pretreatment buffer. The inactive bromoacetyl analog of forskolin 7-bromoacetyl-7-desacetyl-1.9-dideoxyforskolin (1,9-dideoxy-BrAcFsk) did not activate adenylate cyclase, inhibit [3H]forskolin binding, or cause an irreversible loss of [3H]forskolin binding sites. Adenylate cyclase was assayed in membranes from platelets treated with either 10 microM BrAcFsk or 10 microM 1,9-dideoxy-BrAcFsk. The stimulation of adenylate cyclase by prostaglandin E1, guanosine-5'-O-(3-thio)triphosphate, and AIF4 was inhibited by about 50% in membranes from platelets treated with BrAcFsk. However, the stimulation of adenylate cyclase by forskolin was unaffected by preincubation with BrAcFsk. Pretreatment of human platelets with 1,9-dideoxy-BrAcFsk had no effect on the stimulation of adenylate cyclase by prostaglandin E1, AIF4, or forskolin.

Relationship between the fluidity of the membrane lipids and the activity of the membrane-bound proteins: the effects of lidocaine on the adenylate cyclase activity of rat myocardium.

The lidocaine effects on the basal adenylate cyclase activity of the studied membranes depend on the substrate concentration: the drug has an inhibiting effect on non-saturating ATP concentrations, but displays a stimulating effect on the saturating ones. In the presence of maximally stimulating NaF concentrations, lidocaine further stimulates the adenylate cyclase activity through all the ATP concentrations used. In the presence of ATP saturating concentrations, the adenylate cyclase activity stimulated by various Gpp(NH)p concentrations, is inhibited in the presence of lidocaine as well as the enzymic activity stimulated by several l-isoproterenol concentrations in the presence of a fixed Gpp(NH)p concentration.

Interaction of aminoalkylcarbamates of forskolin with adenylyl cyclase: synthesis of an iodinated derivative of forskolin with high affinity for adenylyl cyclase.

7-(2-Aminoethyl)aminocarbonyl-7-desacetylforskolin (7-AEC-Fsk) and 6-(2-aminoethyl)aminocarbonylforskolin (6-AEC-Fsk) were synthesized and tested for their ability to activate adenylyl cyclase and inhibit the high affinity binding of [3H]forskolin to bovine brain membranes. Forskolin and 7-AEC-Fsk were equipotent in activating adenylyl cyclase, with EC50 values of about 4 microM, whereas 6-AEC-Fsk had an EC50 of about 2 microM. 6-AEC-Fsk and 7-AEC-Fsk stimulated adenylyl cyclase about 7-fold over basal levels at 100 microM, whereas forskolin produced a 5-fold stimulation. Forskolin and 6-AEC-Fsk inhibited the binding of [3H]forskolin to bovine brain membranes with Kd values of 41 nM and 28 nM, respectively, whereas 7-AEC-Fsk had a Kd of 83 nM. The 3-(3-iodo-4-hydroxyphenyl)propionamide derivative of 6-AEC-Fsk (6-I-HPP-Fsk) was more potent than forskolin in inhibiting [3H]forskolin binding to bovine brain membranes, with a Kd of 14 nM. 6-AEC-Fsk was reacted with 125I-labeled Bolton-Hunter reagent to produce 6-125I-HPP-Fsk with a specific activity of 2175 Ci/mmol. 6-125I-HPP-Fsk bound to bovine brain membranes with a Kd of 13 nM and a Bmax of 3.8 pmol/mg of protein. Forskolin inhibited the binding of 6-125I-HPP-Fsk to bovine brain membranes with a Kd of 31 nM, whereas 1,9-dideoxyforskolin only slightly inhibited the binding at 10 microM. The binding of 6-125I-HPP-Fsk was not inhibited by agents that inhibit forskolin binding to the glucose transporter, such as D-glucose or cytochalasin B. There was no displaceable binding of 6-125I-HPP-Fsk to red blood cell membranes, which contain a large concentration of the glucose transporter. Pretreatment of bovine brain membranes with an alkylating derivative of forskolin, 7-bromoacetyl-7-desacetylforskolin (BrAcFsk), led to an irreversible decrease in the binding of [3H]forskolin and 6-125I-HPP-Fsk. The time dependence and concentration dependence for the BrAcFsk-induced decrease in [3H]forskolin binding sites were identical to those observed for the decrease in 6-125I-HPP-Fsk binding sites. 6-125I-HPP-Fsk binding was determined in human platelet membranes in the presence of Mg2+ alone and in combination with guanosine 5'-O-(3-thio)triphosphate (GTP gamma S) or AIF4-. The presence of GTP gamma S or AIF4- increased the binding of 6-125I-HPP-Fsk by 4.5-fold and 4-fold, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Efficacy and tolerability of subcutaneous sumatriptan for acute migraine: a comparison between ethnic groups.

OBJECTIVE: To evaluate efficacy and tolerability of subcutaneous sumatriptan 6 mg versus placebo for acute migraine between ethnic groups. BACKGROUND: Patients in previous sumatriptan studies have been predominantly Caucasian and the effects of sumatriptan between different ethnic groups are unknown. METHODS: This was a multicenter, 3-phase, 12-attack study. Phases I and III (inclinic) were randomized, double-blind, placebo-controlled, crossover designs. Phase II (outpatient) was a single-blind design. Sumatriptan was compared to placebo across 2 groups (non-Caucasian and Caucasian) and individual ethnic subgroups (black, Hispanic, and others). Headache response, pain-free response, associated symptoms, and clinical disability were assessed. Tolerability assessments included the incidence of adverse events, physical examinations, vital signs, electrocardiograms, and clinical laboratory data. RESULTS: Two hundred patients treated at least one migraine attack (150 non-Caucasians: 46 blacks, 68 Hispanics, 36 others). Two hours postdose, significantly more inclinic sumatriptan-treated patients reported headache response (non-Caucasians, 81% versus 37% placebo; Caucasians, 87% versus 19% placebo; P<.001) and mild or no clinical disability, compared with placebo (non-Caucasians, 87% versus 50% placebo; Caucasians, 90% versus 38% placebo; P<.001). Blacks (80%), Hispanics (83%), and others (74%) reported similar patterns of headache response at 2 hours. Similar results were reported during the outpatient phase. The incidence of adverse events following sumatriptan during the inclinic phase was similar between ethnic groups (non-Caucasian, 75%; Caucasian, 79%) and higher than placebo (non-Caucasian, 51%; Caucasian, 31%). Overall, adverse events in the outpatient phase of the study were lower than in the inclinic phase. CONCLUSION: Sumatriptan injection is effective and well tolerated in non-Caucasians and Caucasians for the treatment of acute migraine attacks. Only minor differences in efficacy or tolerability were observed between blacks, Hispanics, and others.

Hydrolyzing activities on cAMP in E. coli B cells incubated in the presence of polyamines.

1. Hydrolyzing activities on cAMP were investigated in E. coli B cells incubated in the presence or absence of 10(-5) M spermine, spermidine or putrescine. 2. Bacterial cells incubated in the presence of each of the investigated polyamines show an increase in the PDE (phosphodiesterase) activities already evident after 3 min of incubation, reaching the maximum between 5 and 10 min. disappearing between 15 and 25 min. 3. The stimulating effect is higher in the presence of lower (10(-6) M) substrate concentration (high affinity PDE activities). 4. Kinetic analyses carried out for the "high affinity" PDE activity, indicate that spermidine and putrescine are the most effective on increasing both the Vmax or the apparent Km. 5. Kinetic analysis carried out for the "low affinity" PDE activity, indicate that putrescine is the most active on increasing either the Vmax or the apparent Km and that spermine and spermidine have both quantitatively and qualitatively comparable effects. 6. Analyses, by TLC, of the products of the hydrolytic activities on cyclic AMP (5'-adenosine monophosphate (5'-AMP), adenosine, inosine) indicate that the incubation in the presence of each of three polyamines, results in an increase also of the 5' nucleotidase and adenosine deaminase activity.

Interaction of 7-bromoacetyl-7-desacetylforskolin, and alkylating derivative of forskolin, with bovine brain adenylyl cyclase and human erythrocyte glucose transporter.

7-Bromoacetyl-7-desacetylforskolin (BrAcFsk), an alkylating derivative of forskolin, activated adenylyl cyclase and irreversibly blocked high affinity forskolin binding sites in human platelet membranes and rat brain membranes (Laurenza et al., 1990). Photoincorporation of an iodinated arylazido derivative of forskolin, 125I-6-AIPP-Fsk, into adenylyl cyclase in bovine brain membranes was irreversibly inhibited by BrAcFsk but not by 1,9-dideoxy-BrAcFsk, suggesting that BrAcFsk was reacting specifically with a nucleophilic group(s) at the forskolin binding site of adenylyl cyclase. Immunoblotting with antiforskolin antiserum demonstrated that partially purified bovine brain adenylyl cyclase had incorporated BrAcFsk. The interaction of BrAcFsk with the glucose transporter in human erythrocyte membranes was examined in a similar manner. Photoincorporation of 125I-7-AIPP-Fsk, an iodinated arylazido derivative of forskolin which is specific for the glucose transporter, into the glucose transporter was not irreversibly inhibited by BrAcFsk, suggesting that, in contrast to adenylyl cyclase, there is no reactive nucleophilic group at the forskolin binding site on the human erythrocyte glucose transporter. The immunoblotting procedure with antiforskolin antiserum confirmed that BrAcFsk was not covalently attached to human erythrocyte glucose transporter.

Low insulin concentrations stimulate in vitro the soluble guanylate cyclase activity of rat liver.

The soluble guanylate cyclase activity of rat liver appears to be stimulated in VITRO by insulin at pMolar concentrations, while proinsulin, denaturated insulin or desoctapeptide insulin, are not able to stimulate the studied enzymic activity. Corresponding concentrations of other peptide hormones such as corticotropin (ACTH) or glucagon, either in the absence or in the presence of bacitracin, do not show any effect on the investigated enzymic system. Insulin stimulation of the soluble guanylate cyclase is characterized by a significant increase in the Vmax together with a decrease of the apparent Km. Insulin at low concentrations doesn't affect the cyclic GMP hydrolyzing activity; conversely higher concentrations of the hormone, while exerting a less marked effect on the guanylate cyclase activity, inhibit the cyclic GMP hydrolyzing activity.

Naratriptan is effective and well tolerated in the acute treatment of migraine. Results of a double-blind, placebo-controlled, parallel-group study. Naratriptan S2WA3001 Study Group.

OBJECTIVE: To evaluate the efficacy and tolerability of naratriptan, a novel 5-HT1 agonist, in the acute treatment of migraine. DESIGN/METHODS: Six hundred thirteen migraineurs, diagnosed according to International Headache Society criteria, treated a single migraine attack with naratriptan tablets (2.5 mg, 1 mg, 0.25 mg, or 0.1 mg) or placebo in a randomized, double-blind, placebo-controlled, parallel-group study conducted at 54 United States centers. At dosing and at predetermined intervals beginning 30 minutes postdose, patients recorded migraine pain severity, clinical disability, and presence of associated migraine symptoms. Safety measures included adverse events, physical examinations, vital signs, ECGs, and clinical laboratory tests. RESULTS: Headache relief (moderate or severe pain at dosing reduced to mild or no pain) 4 hours postdose was reported in 60% of patients receiving naratriptan 2.5 mg compared with 50%, 35%, 32%, and 34% of patients receiving naratriptan 1 mg, 0.25 mg, 0.1 mg, and placebo, respectively (P < 0.05 naratriptan 2.5 mg and 1 mg versus placebo, 1 mg versus 0.1 mg, and 2.5 mg versus 0.1 mg and 0.25 mg). Clinical disability 4 hours postdose was reported as mild or none for 70% of patients receiving naratriptan 2.5 mg compared with 63%, 47%, 48%, and 48% of patients receiving naratriptan 1 mg, 0.25 mg, 0.1 mg, or placebo, respectively (P < 0.05 naratriptan 2.5 mg and 1 mg versus placebo, 1 mg versus 0.1 mg, and 2.5 mg versus 0.1 mg and 0.25 mg). Four-hour efficacy for absence of nausea, photophobia, and phonophobia was similar to efficacy for headache relief at each dose. The adverse event profile of each dose of naratriptan was similar to that of placebo. No clinically relevant change in any safety measure was reported. CONCLUSIONS: Naratriptan is effective and well tolerated for the acute treatment of migraine. The 2.5-mg dose appears to offer the optimum ratio of efficacy to tolerability.

Identification of a role of the vitronectin receptor and protein kinase C in the induction of endothelial cell vascular formation.

When cultured on a basement membrane substratum, endothelial cells undergo a rapid series of morphological and functional changes which result in the formation of histotypic tube-like structures, a process which mimics in vivo angiogenesis. Since this process is probably dependent on several cell adhesion and cell signaling phenomena, we examined the roles of integrins and protein kinase C in endothelial cell cord formation. Polyclonal antisera directed against the entire vitronectin (alpha v beta 3) and fibronectin (alpha 5 beta 1) receptors inhibited cord formation. Subunit-specific monoclonal antibodies to alpha v, beta 3, and beta 1 integrin subunits inhibited cord formation, while monoclonal antibodies to alpha 5 did not, which implicated the vitronectin receptor, and not the fibronectin receptor, in vascular formation. Protein kinase C inhibitors inhibited cord formation, while phorbol 12-myristate 13-acetate (PMA) caused endothelial cells to form longer cords. Since the vitronectin receptor has been shown to be phosphorylated in an in vitro system by protein kinase C, the possible functional link between the vitronectin receptor and protein kinase C during cellular morphogenesis was examined. The vitronectin receptor was more highly phosphorylated in cord-forming endothelial cells on basement membrane than in monolayer cells on vitronectin. Furthermore, this phosphorylation was inhibited by protein kinase C inhibitors, and PMA was required to induce vitronectin receptor phosphorylation in endothelial cells cultured on vitronectin. Colocalization studies were also performed using antisera to the vitronectin receptor and antibodies to protein kinase C. Although no strict colocalization was found, protein kinase C was localized in the cytoskeleton of endothelial cells initially plated on basement membrane or on vitronectin, and it translocated to the plasma membrane of C-shaped cord-forming cells on basement membrane. Thus, both the vitronectin receptor and protein kinase C play a role in in vitro cord formation.