Effect of angiotensin converting enzyme inhibitors on quality of life in hypertensive patients. Pharmacodynamic basis

Indoor tanning bed use and risk of food addiction based on the modified Yale Food Addiction Scale

The popularity of indoor tanning may be partly attributed to the addictive characteristics of tanning for some individuals. We aimed to determine the association between frequent indoor tanning, which we view as a surrogate for tanning addiction, and food addiction. A total of 67,910 women were included from the Nurses’ Health Study II. In 2005, we collected information on indoor tanning during high school/college and age 25-35 years, and calculated the average use of indoor tanning during these periods. Food addiction was defined as ≥3 clinically significant symptoms plus clinically significant impairment or distress, assessed in 2009 using a modified version of the Yale Food Addiction Scale. Totally 23.3% (15,822) of the participants reported indoor tanning at high school/college or age 25-35 years. A total of 5,557 (8.2%) women met the criteria for food addiction. We observed a dose–response relationship between frequency of indoor tanning and the likelihood of food addiction (P_trend < 0.0001), independent of depression, BMI, and other confounders. Compared with never indoor tanners, the odds ratio (95% confidence interval) of food addiction was 1.07 (0.99-1.17) for average indoor tanning 1-2 times/year, 1.25 (1.09-1.43) for 3-5 times/year, 1.34 (1.14-1.56) for 6-11 times/year, 1.61 (1.35-1.91) for 12-23 times/year, and 2.98 (1.95-4.57) for 24 or more times/year. Frequent indoor tanning before or at early adulthood is associated with prevalence of food addiction at middle age. Our data support the addictive property of frequent indoor tanning, which may guide intervention strategies to curb indoor tanning and prevent skin cancer.

Angiotensin II suppresses long-term depression in the lateral amygdala of mice via L-type calcium channels

Previously we have shown that angiotensin II (Ang II) suppresses long-term potentiation (LTP) in the lateral nucleus of the amygdala (LA) of horizontal slices. This study examines the effect of Ang II on long-term depression (LTD) in the LA. Low frequency stimulation (1 Hz, 15 min; LFS) applied to fibers running within the LA induced a long-lasting reduction of the amplitudes of field potentials in the LA of mice. We have previously shown that this LTD is sensitive to the NMDA receptor blocker D-AP5 and is dependent on group II mGlu receptors. Ang II blocked dose-dependent LTD. Losartan, an AT1 receptor antagonist, blocked the Ang II-induced suppression of LTD, whereas PD 123 319, an AT2 receptor antagonist, had no effect. Co-administration of nifedipine, an L-type calcium channel antagonist, abolished Ang II-induced suppression of LTD. When applied alone nifedipine reduced the magnitude of LA-LTD. According to our previous results, stimulation of external capsule (EC) fibers in rats did not cause LTD in mice. Similarly, Ang II did not induce long-lasting changes of activity when EC stimulation site was used. The results support the view that angiotensins are involved in mechanisms of learning and memory including the plasticity changes in the LA.

Influence of temocapril on cultured ventral spinal cord neurons

Temocapril, a angiotensin-converting enzyme (ACE) inhibitor, was tested for neurotrophic activity in primary explant cultures of ventral spinal cord of fetal rats (VSCC). Temocapril had a remarkable effect on neurite outgrowth with a 4.2- to 5.1-fold increased over that of control VSCC at their effective concentrations. In temocapril-treated VSCC, choline acetyltransferase (ChAT) activity was also increased 2.4-3.2 times over that of control at 10(-9) and 10(-8) M, respectively. Our data suggest that temocapril is a candidate for neurotrophic factors on spinal motor neurons in vitro. A possible therapeutic role for temocapril in damaged motor neurons, such as in motor neuropathy and amyotrophic lateral sclerosis, remains to be defined.

Temocapril prevents motor neuron damage and upregulation of cyclooxygenase-II in glutamate-induced neurotoxicity

To examine the possible neuroprotective effect of temocapril, one kind of angiotensin-converting enzyme inhibitor, against glutamate-induced neurotoxicity, we analyzed the pharmacologic utility of temocapril in a post-natal organotypic culture model of motor neuron degeneration. Treatment with 10(-5) M of glutamate resulted in a motor neuron loss and decreased activity of choline acetyltransferase (ChAT). Cotreatment of 10(-5) M of glutamate and temocapril revealed protective effect on motor neuron death and decreased activity of ChAT. Next we performed reverse transcription-PCR analysis for cyclooxygenase-II (COX-II). COD-II mRNA was upregulated in glutamate-treated culture. Cotreatment with temocapril and glutamate inhibited upregulation of COX-II. Taken together, temocapril may have therapeutic potential for diseases which associate with upregulation of COX-II, in addition to its role in glutamate excitotoxicity.

Extracellular matrix molecules, long-term potentiation, memory consolidation and the brain angiotensin system

Considerable evidence now suggests an interrelationship among long-term potentiation (LTP), extracellular matrix (ECM) reconfiguration, synaptogenesis, and memory consolidation within the mammalian central nervous system. Extracellular matrix molecules provide the scaffolding necessary to permit synaptic remodeling and contribute to the regulation of ionic and nutritional homeostasis of surrounding cells. These molecules also facilitate cellular proliferation, movement, differentiation, and apoptosis. The present review initially focuses on characterizing the ECM and the roles of cell adhesion molecules (CAMs), matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs), in the maintenance and degradation of the ECM. The induction and maintenance of LTP is described. Debate continues over whether LTP results in some form of synaptic strengthening and in turn promotes memory consolidation. Next, the contribution of CAMs and TIMPs to the facilitation of LTP and memory consolidation is discussed. Finally, possible roles for angiotensins, MMPs, and tissue plasminogen activators in the facilitation of LTP and memory consolidation are described. These enzymatic pathways appear to be very important to an understanding of dysfunctional memory diseases such as Alzheimer's disease, multiple sclerosis, brain tumors, and infections.

Enalapril and moexipril protect from free radical-induced neuronal damage in vitro and reduce ischemic brain injury in mice and rats

Angiotensin-converting enzyme inhibitors have been demonstrated to protect spontaneously hypertensive rats from cerebral ischemia. The present study investigated the protective effect of enalapril and moexipril in models of permanent focal cerebral ischemia in normotensive mice and rats. To elucidate the mechanism of neuroprotection the influence of these angiotensin-converting enzyme inhibitors on glutamate-, staurosporine- or Fe2+/3+-induced generation of reactive oxygen species and neuronal cell death in primary cultures from chick embryo telencephalons was studied. Treatment with moexipril or enalapril dose-dependently reduced the percentage of damaged neurons, as well as mitochondrial reactive oxygen species generation induced by glutamate, staurosporine or Fe2+/3+. Furthermore, moexipril and enalapril attenuated staurosporine-induced neuronal apoptosis as determined by nuclear staining with Hoechst 33258. In mice, 1 h pretreatment with enalapril (0.03 mg/kg) or moexipril (0.3 mg/kg) significantly reduced brain damage after focal ischemia as compared to control animals. Additionally, moexipril (0.01 mg/kg) was able to reduce the infarct volume in the rat model after focal cerebral ischemia. The results of the present study indicate that the angiotensin-converting enzyme inhibitors enalapril and moexipril promote neuronal survival due to radical scavenging properties.

Angiotensin II inhibits long-term potentiation within the lateral nucleus of the amygdala through AT1 receptors

Long-term potentiation (LTP) of field potentials in the lateral nucleus of the amygdala (LA) evoked by brief tetanic stimuli of the LA were observed in horizontal rat brain slices. The amplitude of field potentials was significantly enhanced after repetitive stimulation. When angiotensin II was administrated the induction of LTP was suppressed. This inhibition of LTP was mediated by angiotensin II because it could be blocked by the coadministration of saralasin, an nonspecific angiotensin II antagonist. The coadministration of losartan, a competitive antagonist of the AT1 receptor subtype, concomitant with angiotensin II was also able to block this inhibition. The coadministration of the AT2 receptor antagonist PD 123,319 failed to block the inhibition of LTP.