A novel class of Na+ and Ca2+ channel dual blockers with highly potent anti-ischemic effects

Prevention of hyperglycemic signal pathways in metabolic syndrome carotid artery of rats

Obesity is the major risk factor for metabolic syndrome and atherosclerotic cardiocerebrovascular diseases and induces insulin resistance characterized by a dysfunction of insulin to activate insulin receptor /insulin receptor substrate 1(IRS-1)/phosphoinositide 3-kinase (PI3K)/Akt pathway. Zucker fatty rats (8 weeks) were treated with vehicle (0.5 % methyl cellulose in physiological saline, p.o.), amlodipine (3 mg/kg/day, p.o.), atorvastatin (10 mg/kg/day, p.o.), or the combination of amlodipine plus atorvastatin (3 + 10 mg/kg/day, p.o.) for 28 days, and anti-insulin-like growth factor 1 (IGF-1)/IRS-1/PI3K/Akt pathways were evaluated. Our present immunohistochemical study first demonstrated that a combination of amlodipine plus atorvastatin treatment prevented an arteriosclerotic process compared to the single treatment with amlodipine or atorvastatin with strong recoveries of pTyr IRS-1, pPI3K, and pAkt expressions and with remarkable restraints of IGF-1 and pSer IRS-1. As a result, combination therapy with amlodipine plus atorvastatin showed a strong synergistic effect to prevent atherosclerotic processes. The present study newly suggests a synergistic benefit of combination therapy with amlodipine plus atorvastatin for strong prevention of atherosclerotic processes, which could reduce the clinical risk of cerebrovascular events for obesity patients.

Protection against ischemic stroke damage by synergistic treatment with amlodipine plus atorvastatin in Zucker metabolic rat

Ischemic stroke is a major neurologic disorder and a leading cause of disability and death in the world. We compared neuroprotective effects of single or combination therapy of amlodipine (AM) and atorvastatin (AT) in such a metabolic syndrome model Zucker rat. The animals were pretreated with vehicle, AM, AT, or the combination of AM plus AT for 28days, and physical and serum parameters were analyzed, then 90min of transient middle cerebral artery occlusion (tMCAO), was performed followed by immunohistochemical analyses at 24h. Without affecting serum levels of lipids, adiponectin, and leptin, the combination therapy of AM plus AT ameliorated the post-ischemic brain weight increase. The single treatment with AM or AT itself exerted neuroprotective effects with reducing inductions of MMP-9 and AT2R, as well as with preserving collagen IV, and the combination therapy of AM plus AT showed a further synergistic benefit against acute ischemic neural damages. Single AT was more protective on these 3 molecules than single AM at this time point of 24h after tMCAO. Thus, the combination therapy with AM plus AT extended the neuroprotectives effect of single treatment with AM or AT on a part of neurovascular unit and a hypertension-related receptor.

Multifunctional drugs with different CNS targets for neuropsychiatric disorders

The multiple disease etiologies that lead to neuropsychiatric disorders, such as Parkinson's and Alzheimer's disease, amyotrophic lateral sclerosis, Huntington disease, schizophrenia, depressive illness and stroke, offer significant challenges to drug discovery efforts aimed at preventing or even reversing the progression of these disorders. Transcriptomic tools and proteomic profiling have clearly indicated that such diseases are multifactorial in origin. Further, they are thought to be initiated by a cascade of molecular events that involve several neurotransmitter systems. In response to this complexity, a new paradigm has recently emerged that challenges the widely held assumption that 'silver bullet' agents are superior to 'dirty drugs' in therapeutic approaches aimed at the prevention or treatment of neuropsychiatric diseases. A similar pattern of drug development has occurred in strategies for the treatment of cancer, AIDS and cardiovascular diseases. In this review, we offer an overview of therapeutic strategies and novel investigative drugs discovered or developed in our own and other laboratories, that address multiple CNS etiological targets associated with an array of neuropsychiatric disorders.

Pharmacological characterization of recombinant N-type calcium channel (Cav2.2) mediated calcium mobilization using FLIPR

The N-type voltage-gated calcium channel (Ca(v)2.2) functions in neurons to regulate neurotransmitter release. It comprises a clinically relevant target for chronic pain. We have validated a calcium mobilization approach to assessing Ca(v)2.2 pharmacology in two stable Ca(v)2.2 cell lines: alpha1(B), alpha2delta, beta(3)-HEK-293 and alpha1(B), beta(3)-HEK-293. Ca(v)2.2 channels were opened by addition of KCl and Ca(2+) mobilization was measured by Fluo-4 fluorescence on a fluorescence imaging plate reader (FLIPR(96)). Ca(v)2.2 expression and biophysics were confirmed by patch-clamp electrophysiology (EP). Both cell lines responded to KCl with adequate signal-to-background. Signals from both cell lines were inhibited by omega-conotoxin (ctx)-MVIIa and omega-conotoxin (ctx)-GVIa with IC(50) values of 1.8 and 1nM, respectively, for the three-subunit stable, and 0.9 and 0.6nM, respectively, for the two-subunit stable. Other known Ca(v)2.2 blockers were characterized including cadmium, flunarizine, fluspirilene, and mibefradil. IC(50) values correlated with literature EP-derived values. Novel Ca(v)2.2 pharmacology was identified in classes of compounds with other primary pharmacological activities, including Na(+) channel inhibitors and antidepressants. Novel Na(+) channel compounds with high potency at Ca(v)2.2 were identified in the phenoxyphenyl pyridine, phenoxyphenyl pyrazole, and other classes. The highest potency at Ca(v)2.2 tricyclic antidepressant identified was desipramine.

Drug targets in the voltage-gated calcium channel family: why some are and some are not

The L-type calcium channel antagonists have been, and continue to be, a very successful group of therapeutic agents targeted at cardiovascular disorders, notably angina and hypertension. The discovery that the voltage-gated calcium channels are a large and widely distributed family with important roles in both the peripheral and central nervous systems has initiated a major search for drugs active at other calcium channel types directed at disorders of the central nervous system, including pain, epilepsy, and stroke. These efforts have not been therapeutically successful thus far, and small molecule equivalents of the L-type blockers nifedipine, diltiazem, and verapamil directed at non-L-type channels have not been found. The underlying reasons for this are discussed together with suggestions for new directions, including fertility control, oxygen-sensitive channels, and calcium channel activators.

Synthesis and biological evaluation of new 4-arylpiperidines and 4-aryl-4-piperidinols: dual Na(+) and Ca(2+) channel blockers with reduced affinity for dopamine D(2) receptors

A series of novel 4-arylpiperidines and 4-aryl-4-piperidinols (2a-f, 3a-f and 4a-f) was synthesized and evaluated for blocking effects on both neuronal Na(+) and T-type Ca(2+) channels and binding affinity for dopamine D(2) receptors. Most of the compounds blockaded both ion channels with potency greater than or equal to flunarizine 1a which was adopted as a reference standard. In addition, these compounds had significantly reduced affinity for dopamine D(2) receptors which is common in this class of structure. Compounds 2a-f, 3a-f and 4a-f exhibited potent anticonvulsant effects following systemic (ip) administration on audiogenic seizures in DBA/2 mice, indicating their excellent brain permeability. The neuroprotective activity of 2a, 3a and 4a was also assessed in a transient middle cerebral artery occlusion (MCAO) model. These compounds significantly reduced neuronal damage without affecting ischemic hyperthemia, while flunarizine 1a produced only minor reductions. In particular, 4a had 1.7-fold the potency in this MCAO model but only 1/20 the affinity for dopamine D(2) receptors of 1a. The superposition of 2a, 3a and 4a on the basis of analyses of systematic conformation and similar structure has revealed that the cinnamyl, phenacyl and phenoxypropanol groups are likely to be structurally and biologically equivalent. Moreover, the superposition of 2a and 2f shows that diphenyl ether and biphenyl groups occupy a similar space, suggesting that both groups act as a bioisostere for the blockade of ion channels; however, this is not the case for dopamine D(2) receptors since only biphenyl compounds such as 2f had high affinity similar to flunarizine 1a. Compound 4a (SUN N5030) has a good pharmacological profile and may be useful in the alleviation and treatment of ischemic diseases.

Molecular pharmacology of T-type Ca2+ channels

Over the past few years increasing attention has been focused on T-type calcium channels and their possible physiological and pathophysiological roles. Efforts toward elucidating the exact role(s) of these calcium channels have been hampered by the lack of T-type specific antagonists, resulting in the subsequent use of less selective calcium channel antagonists. In addition, the activity of these blockers often varies with cell or tissue type, as well as recording conditions. This review summarizes a variety of compounds that exhibit varying degrees of blocking activity towards T-type Ca2+ channels. It is designed as an aid for researchers in need of antagonists to study the biophysical and pathological nature of T-type channels, as well as a starting point for those attempting to develop potent and selective antagonists of the channel.