Temporal lobe epilepsy is the most prevalent seizure disorder in adults. Compromised inhibitory neurotransmitter function in the hippocampus contributes to the hyperexcitability generating this condition, but the underlying molecular mechanisms are unknown. Combining patch-clamp recording and single-cell mRNA amplification (aRNA) techniques in single dentate granule cells, we demonstrate that expression of GABA(A) receptor subunit mRNAs is substantially altered in neurons from epileptic rats. These changes in gene expression precede epilepsy onset by weeks and correlate with profound alterations in receptor function, indicating that aberrant GABA(A) receptor expression and function has an essential role in the process of epileptogenesis.

Men have higher blood pressure than women through much of life regardless of race and ethnicity. This is a robust and highly conserved sex difference that it is also observed across species including dogs, rats, mice and chickens and it is found in induced, genetic and transgenic animal models of hypertension. Not only do the differences between the ovarian and testicular hormonal milieu contribute to this sexual dimorphism in blood pressure, the sex chromosomes also play a role in and of themselves. This review primarily focuses on epidemiological studies of blood pressure in men and women and experimental models of hypertension in both sexes. Gaps in current knowledge regarding what underlie male-female differences in blood pressure control are discussed. Elucidating the mechanisms underlying sex differences in hypertension may lead to the development of anti-hypertensives tailored to one's sex and ultimately to improved therapeutic strategies for treating this disease and preventing its devastating consequences.

The cytoplasmic tails of the influenza virus glycoproteins hemagglutinin (HA) and neuraminidase (NA) are highly conserved in sequence for all virus subtypes and it is believed that assembly of this enveloped virus depends on interactions of these domains with cytoplasmic viral components. However, it is possible to rescue altered influenza viruses lacking either the HA or NA cytoplasmic tails. We have obtained an influenza virus that lacks both the cytoplasmic tail of HA and NA. Particle production is reduced ∼10‐fold but these particles, although having a fairly normal protein composition, are greatly elongated and of extended irregular shape. We propose a model in which the interactions of the cytoplasmic tails of HA and NA with an internal viral component are so important for spherical virion shape that there is dual redundancy in the interactions.

BackgroundAngotensin converting enzyme 2 (ACE2) is a newly discovered monocarboxypeptidase that counteracts the vasoconstrictor effects of angiotensin II (Ang II) by converting Ang II to Ang-(1-7) in the kidney and other tissues.MethodsACE2 activity from renal homogenates was investigated by using the fluorogenic peptide substrate Mca-YVADAPK(Dnp)-OH, where Mca is (7-methoxycoumarin-4-yl)-acetyl and Dnp is 2,4-dinitrophenyl.ResultsWe found that ACE2 activity expressed in relative fluorescence units (RFU) in the MF1 mouse is higher in the male (M) compared to the female (F) kidney [ACE2 (RFU/min/μg protein): M 18.1 ± 1.0 versus F 11.1 ± 0.39; P < 0.0001; n = 6]. Substrate concentration curves revealed that the higher ACE2 activity in the male was due to increased ACE2 enzyme velocity (Vmax) rather than increased substrate affinity (Km). We used the four core genotypes mouse model in which gonadal sex (ovaries versus testes) is separated from the sex chromosome complement enabling comparisons among XX and XY gonadal females and XX and XY gonadal males. Renal ACE2 activity was greater in the male than the female kidney, regardless of the sex chromosome complement [ACE2 (RFU/min/μg protein): intact-XX-F, 7.59 ± 0.37; intact-XY-F, 7.43 ± 0.53; intact-XX-M, 12.1 ± 0.62; intact-XY-M, 12.7 ± 1.5; n = 4-6/group; P < 0.0001, F versus M, by two-way ANOVA]. Enzyme activity was increased in gonadectomized (GDX) female mice regardless of the sex chromosome complement whereas no effect of gonadectomy was observed in the males [ACE2 (RFU/min/μg protein): GDX-XX-F, 12.4 ± 1.2; GDX-XY-F, 11.1 ± 0.76; GDX-XX-M, 13.2 ± 0.97; GDX-XY-M, 11.6 ± 0.81; n = 6/group]. 17β-oestradiol (E2) treatment of GDX mice resulted in ACE2 activity that was only 40% of the activity found in the GDX mice, regardless of their being male or female, and was independent of the sex chromosome complement [ACE2 (RFU/min/μg protein): GDX+E2-XX-F, 5.56 ± 1.0; GDX+E2-XY-F, 4.60 ± 0.52; GDX+E2-XX-M, 5.35 ± 0.70; GDX+E2-XY-M, 5.12 ± 0.47; n = 6/group].ConclusionsOur findings suggest sex differences in renal ACE2 activity in intact mice are due, at least in part, to the presence of E2 in the ovarian hormone milieu and not to the testicular milieu or to differences in sex chromosome dosage (2X versus 1X; 0Y versus 1Y). E2 regulation of renal ACE2 has particular implications for women across their life span since this hormone changes radically during puberty, pregnancy and menopause.

L-Glutamic acid decarboxylase (GAD) exists as both membraneassociated and soluble forms in the mammalian brain. Here, we propose that there is a functional and structural coupling between the synthesis of ␥-aminobutyric acid (GABA) by membraneassociated GAD and its packaging into synaptic vesicles (SVs) by vesicular GABA transporter (VGAT). This notion is supported by the following observations. First, newly synthesized [ 3 H]GABA from [ 3 H]L-glutamate by membrane-associated GAD is taken up preferentially over preexisting GABA by using immunoaffinity-purified GABAergic SVs. Second, the activity of SV-associated GAD and VGAT seems to be coupled because inhibition of GAD also decreases VGAT activity. Third, VGAT and SV-associated Ca 2؉ ͞ calmodulin-dependent kinase II have been found to form a protein complex with GAD. A model is also proposed to link the neuronal stimulation to enhanced synthesis and packaging of GABA into SVs.T he rate-limiting enzyme L-glutamic acid decarboxylase (GAD, EC 4.1.1.15) is involved in the synthesis of ␥-aminobutyric acid (GABA), a major inhibitory neurotransmitter in the mammalian brain. There are two well-characterized GAD isoforms in the human brain, namely GAD 65 and GAD 67 (referring to GAD with a molecular mass of 65 kDa and 67 kDa, respectively) (1). Both GAD 65 and GAD 67 are present as homodimers or heterodimers in soluble GAD (SGAD) and membrane-associated GAD (MGAD) pools (2-4). The ratio of GAD 65 to GAD 67 is higher in synaptic vesicle (SV) fractions than in the cytosol (5). Some studies suggest that GAD 65 binds to the membranes (6, 7) and that GAD 67 subsequently interacts with MGAD 65 (2, 6). However, the nature of anchorage of GAD to membranes and its physiological significance is still not well understood. GAD is not considered to be an integral membrane protein because it lacks a stretch of hydrophobic amino acids long enough to span the membrane. Subpopulations of GAD 65 and GAD 67 remain firmly anchored to membranes despite various ionic extraction methods (2,4,8). The interaction of GAD with membranes was reported to be through ionic (9-11), hydrophobic (12, 13), protein phosphorylation (14), or proteinprotein interaction (15). Previously, we reported that MGAD is activated by phosphorylation that requires an electrochemical gradient across the SV membrane (7). A model for the anchoring mechanism of GAD to SV and its role as a link between GABA synthesis and storage in nerve terminals was also proposed (15). The evidence presented here will demonstrate that GABA synthesized by SV-associated GAD is preferentially transported into the SV by vesicular GABA transporters (VGATs). We have also demonstrated that VGAT, a 10-transmembrane helix protein (16), forms a protein complex with GAD on the SV and could be involved in the anchorage of MGAD to the SV. The formation of this GAD protein complex ensures an efficient coupling between GABA synthesis and packaging into the SV. Materials and MethodsPreparation of SVs. SVs were purified from whole rat brain (Sprague-Dawle...

Abstract-The ovariectomized (OVX) Dahl salt-sensitive (DS) rat fed a low-salt diet is a model of postmenopausal hypertension. In addition to estrogen loss, aging can also contribute to postmenopausal hypertension. We hypothesized that: (1) female DS rats on a low-salt diet become hypertensive with age; (2) ovariectomy accelerates age-dependent hypertension in the DS rat caused by estrogen depletion; and (3) this hypertension correlates with increased type 1 angiotensin receptor (AT 1 R) number (Bmax). Blood pressure was monitored by telemetry from 3 to 12 months and AT 1 R Bmax was determined by Scatchard analysis in glomeruli and adrenal cortex. Three groups of DS rats were studied: intact, OVX, and 17␤-estradiol-replaced OVX (OVXϩE). In intact rats, aging to 12 months resulted in hypertension (159Ϯ6 mm Hg) and an 82% decrease in estrogen. Blood pressure in OVX was significantly higher than OVXϩE through 12 months of age (173Ϯ4 versus 150Ϯ8 mm Hg). At 4 months, OVX increased AT 1 R Bmax compared with intact and OVXϩE in both glomeruli and adrenal cortex. Aging also increased AT 1 R Bmax in these tissues in intact rats. In summary, female DS rats fed a low-salt diet have hypertension develop with age, that is accelerated by OVX and attenuated by estrogen replacement. Concurrently, AT 1 Rs are upregulated by age and OVX, which is prevented by estrogen replacement. This study suggests that an increased activity of the renin angiotensin system contributes to the development of hypertension, and estrogen protects against this process. Key Words: aging Ⅲ Dahl rats Ⅲ hypertension, sodium-dependent Ⅲ estrogen Ⅲ renin-angiotensin system T he prevalence of hypertension in premenopausal women is lower compared with men of the same age. 1 After menopause, the incidence of hypertension in women doubles and becomes similar to men, suggesting that the loss of female gonadal steroids caused by menopause are a risk factor for postmenopausal hypertension. 2 In addition, there is evidence that salt-sensitivity also contributes to postmenopausal hypertension. 3 The mechanisms of postmenopausal hypertension are not well-understood and few animal models exist to study this phenomenon. We have shown that adult (4 months) female normotensive Dahl salt-sensitive (DS) rats maintained on a low-salt (LS) diet become hypertensive after ovariectomy (OVX). 4 Thus, the ovariectomized DS rat serves as an experimental model of postmenopausal hypertension. Furthermore, this is the first animal model in which OVX results in spontaneous hypertension. These studies suggest that salt-sensitive premenopausal women may be protected against the development of hypertension because of the presence of female gonadal steroids and that after menopause, the protective effects of these hormones are lost, thus contributing to the development of hypertension. Although these observations implicate a role for estrogen (E), the effects of aging on the regulation of blood pressure could also contribute to the development of salt-sensitive hypertension in postmenopa...

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Respiratory syncytial virus (RSV) encodes several proteins that lack well-defined functions; these include NS1, NS2, SH, and M2-2. Previous work has demonstrated that NS2, SH, and M2-2 can each be deleted from RSV genome and thus are considered as accessory proteins. To determine whether RSV can replicate efficiently when two or more transcriptional units are deleted, we removed NS1, NS2, SH, and M2-2 genes individually and in different combinations from an infectious cDNA clone derived from human RSV A2 strain. The following six mutants with two or more genes deleted were obtained: DeltaNS1NS2, DeltaM2-2SH, DeltaM2-2NS2, DeltaSHNS1, DeltaSHNS2, and DeltaSHNS1NS2. Deletion of M2-2 together with NS1 was detrimental to RSV replication. It was not possible to obtain a recombinant RSV when all four genes were deleted. All of the double and triple deletion mutants exhibited reduced replication and small plaque morphology in vitro. Replication of these deletion mutants was more reduced in HEp-2 cells than in Vero cells. Among the 10 single and multiple gene deletion mutants obtained, DeltaM2-2NS2 was most attenuated. DeltaM2-2NS2 formed barely visible plaques in HEp-2 cells and had a reduction of titer of 3 log(10) compared with the wild-type recombinant RSV in infected HEp-2 cells. When inoculated intranasally into cotton rats, all of the deletion mutants were attenuated in the respiratory tract. Our data indicated that the NS1, NS2, SH, and M2-2 proteins, although dispensable for virus replication in vitro, provide auxiliary functions for efficient RSV replication.