Autonomic dysfunction is involved in the onset of salt-sensitive hypertension as baroreflex sensitivity (BRS) is blunted in salt-sensitive hypertension. However, salt sensitivity exhibits sex disparity because in salt-sensitive hypertension, blood pressure (BP) is usually higher in males when compared with females. The mechanism(s) underlying this sexual dimorphism is not clear. We, therefore, designed this study to determine BRS in weanling male Sprague – Dawley rats that were either bilaterally orchidectomized or sham-operated (under ketamine and xylazine anaesthesia (90 mg and 10 mg/kg/body weight i.m) respectively, with or without testosterone replacement (10 mg/kg sustanon 250® i.m once in 3 weeks) and were placed on normal (0.3%) or high (8%) NaCl diet for 6 weeks. Blood pressure (BP) and heart rate (HR) were measured via arterial cannulation under urethane and α-chloralose anesthesia (5 ml/kg body weight i.p). BRS was determined as change in HR per unit change in BP in response to 30 seconds bilateral common carotid artery occlusion (BCCO). Serum concentration of testosterone was measured using enzyme-linked immunosorbent assay (ELISA). High salt diet (HSD) increased both the basal BP and peak BP after BCCO when compared with control. Orchidectomy attenuated but testosterone replacement restored the elevated BP in rats fed HSD. HSD blunted BRS to BCCO. However, this effect of HSD was lost in the absence of testosterone as there was no significant difference in BRS between rat fed a normal or high salt diet. Our results suggest that blunting of the BRS may be one of the mechanisms by which testosterone promotes salt-induced hypertension and serves as one of the bases for sex disparity in salt-sensitive hypertension.

Background: There is paucity of information on how exposure to high environmental temperature interacts with high dietary salt to influence cardiovascular outcome in the face of global warming. Method: This study investigated the impact of high environmental temperature (HET) on the cardio- renal indices of an animal model of hypertension (fed on high salt diet, HSD), and evaluated the effectiveness of angiotensin II receptor blocker (ARB), telmisartan, in modulating these indices. Fifty-six male Sprague Dawley rats (70-90g , 7 week old) were randomly assigned into seven groups of 8 rats, which include control rats (I), fed 0.3% NaCl diet; salt loaded rats (II), fed with 8% NaCl (high salt) diet; Heat rats (III), exposed to HET (37.5-38.5oC) 4 hours daily per week; salt loaded + Heat rats (IV), fed with 8% NaCl diet and exposed to HET daily. Next, salt loaded + ARB rats (V) , fed 8% NaCl diet and treated with telmisartan (30mg/kg); Heat +ARB rats, exposed to HET and treated with telmisartan (30mg/kg); salt loaded +HET+ARB rats (VI), fed with 8% NaCl diet, exposed to HET and treated with telmisartan (30mg/kg). Experiment lasted 8 weeks. Blood Pressure and heart rate were determined invasively and electrolytes by selective ion electrode method. Data analyzed using ANOVA, with P<0.05 significant. Results: Systolic and Diastolic BP, Mean Arterial Pressure, Rate Pressures Product (RPP) (P<0.05), and plasma Na+ (P<0.05) were significantly higher with associated suppressed Na+ excretion (P<0.05) in salt loaded rats exposed to HET compared to rats fed a high salt diet alone. Telmisartan significantly attenuated the elevated blood (P<0.05) and RPP (P<0.05), in the HSD rats exposed to HET, with no corresponding reduction in the rats fed a HSD alone. Conclusion: This indicates that chronic exposure to hot environment exaggerated cardiovascular response to high salt diet possibly via angiotensin II pathway with consequent enhanced ARB action. Keywords: Angiotensin II receptor; high salt diet; hot environment; environmental temperature; heat exposure; hypertension

Background: Prevalence of hypertension is higher among Sub-Saharan Africans than whites and there is a sex difference in the prevalence. Though, salt retention has been implicated in pathogenesis of hypertension, the basis is not completely known. Atrial natriuretic peptide (ANP) might play a role. Method: 43 apparently healthy normotensive male and female Nigerians and 37 aged-matched hypertensive counterparts were orally administered 11.6g of dietary salt each per day for 5 days. Their plasma ANP levels, heart rate (HR), systolic (SBP), diastolic (DBP) and mean arterial blood pressure (MABP) were determined before and after salt loading. Results: Normotensive and hypertensive male and female subjects had similar basal ANP levels. However, salt loading significantly raised the ANP concentrations (p = 0.0001) in normotensive subjects but not significantly in hypertensive counterparts. ANP levels rose significantly in the normotensive males (p = 0.0024) and females (p = 0.0002) but not significantly in the hypertensive counterparts. Besides, salt significantly decreased HR in normotensive (p = 0.0095) and hypertensive (p = 0.0397) subjects but increased SBP (p < 0.01) and MABP (p< 0.01) in both study groups and DBP (p = 0.0014) in hypertensive group only. SBP, DBP and MABP were all significantly elevated (p < 0.05) in hypertensive males and females but not significantly in normotensive females. Conclusion: Although, basal ANP levels were similar in the study normotensive and hypertensive subjects, other findings in this study suggest that ANP as well as female gender could ameliorate increased blood pressure response to salt loading especially in a normotensive state. Keywords: Atrial natriuretic peptide, blood pressure, salt loading, gender, hypertension

It is uncertain if exercise can influence the occurrence of T2DM in offspring of diabetic parents. Therefore this study was designed to assess the effect of exercise on skinfold thickness of offspring of T2DM parents compared with those of non-diabetic parents. This study involved convenience sampling of 50 offspring of T2DM parents attending University College Hospital, Ibadan and 50 offspring of nondiabetic parents who were undergraduate students of the University of Ibadan, Nigeria. Participants were randomly assigned into four groups using convenience sampling method: 25 Normal-weight Offspring of Non-Diabetic Parents (NONDP), 25 Normal-weight Offspring of Diabetic Parents (NODP), 25 Overweight Offspring of Non-Diabetic Parents (OONDP) and 25 Overweight Offspring of Diabetic Parents (OODP). Each participant followed a protocol of graded exercise using the “Tummy trimmer” everyday spending 30-45 minutes daily for 24 weeks. 4 sites of skinfold thickness (supra-iliac, Biceps, Triceps and sub-scapula) were measured by skinfold caliper. Weight and Body Mass Index (BMI) were estimated using standard methods at baseline, 6 weeks, 12 weeks, 18 weeks and 24 weeks, respectively. Data were analyzed using descriptive statistic and repeated ANOVA with p-value at n less than 0.05. The results indicate that compared to baseline, there were reductions at the four sites of skinfold thickness measurements (supra-iliac, Biceps, Triceps and sub-scapular). At supra-iliac site, skinfold thickness in NONDPreductions was from 7.16 mm ± 2.02 to 6.60 mm ± 4.40. The reduction trend for supra-iliac, Biceps, triceps and subscapular skinfold sites in NONDP were 0.56 mm, 0.79 mm, 1.66 mm and 0.19 mm respectively. While the reduction trend for supra-iliac, Biceps, triceps and subscapular skinfold sites in OODP were 0.56 mm, 1.10 mm, 2.06 mm and 1.52 mm respectively. At subscapular site, the average skinfold thickness reduction trend was 0.19 mm in control group 1.53 mm in test group. Thus, graded exercise reduced skinfold thickness in all the groups. The clinical importance of this in prevention of DM among offspring of diabetic parents is quite promising.Key words: Graded exercise, Diabetic parents' offspring, BMI, skinfold thickness,

Errata: Packed Cell Volume in Rheumatoid Arthritis Patients at First PresentationOguntona A.S., Fawole A.E. and Sobowale TThe above titled paper was published in Vol 74, No 1-2, 2018, edition with some texts missing on paragraph 4 of page 14. The affected page is corrected and hereby republished in this edition.

Background: One of the mechanisms by which high salt diet (HSD) induces hypertension is by increasing the generation of reactive oxygen species (ROS). Salt sensitivity exhibits sex difference which is higher in males when compared with females. Likewise, sex disparity in oxidative stress has also been suggested. However, the role of the sex steroids in these sex differences is not clear. Therefore, experiments were designed to assess the role of testosterone on the oxidative status of male rats fed a high salt diet. Methods: Weanling male Sprague-Dawley rats were either sham-operated or orchidectomised under (90mg/kg bodyweight ketamine and 10mg/kg bodyweight xylazine i.p) anesthesia, with or without testosterone replacement (10mg/kg sustanon 250® i.m) once in 3 weeks. They were placed on a diet with normal 0.3% or high 8% NaCl content for 6 weeks. Blood pressure (BP) was measured via arterial cannulation. Levels of lipid peroxidation (LP), superoxide dismutase (SOD), bilirubin and testosterone were measured in the serum. Results: Orchidectomy attenuated the BP elevating effect of a high salt diet, but concomitant replacement of testosterone in orchdectomised rats restored the BP values towards that observed in sham-orchidectomised animal. Orchidectomy abolished while testosterone replacement re-established the significant increase (p<0.001) in LP of the HSD group when compared with the control. High salt diet significantly reduced (p<0.01) the serum levels of SOD. Orchidectomy prevented the reduction in SOD level effect of a high salt diet but testosterone replacement re-established it. Findings from this study show that orchidectomy reduced oxidative stress in male Sprague-Dawley rats fed a high salt diet suggesting a role for testosterone in ROS generating effect of a high salt diet. Keywords: Bilirubin, Hypertension, Lipid peroxidation, Orchidectomy, Oxidative stress, Super oxide dismutase, Testosterone

Low birth weight has been reported in offspring of low salt fed rats.This study investigated the levels of maternal growth factors in rats fed with low salt and high salt diet and the outcome of their offspring. Seventy-two female rats were acclimatized and divided into three groups of control (0.3% salt), low salt diet (0.14% salt) and high salt diet (8% salt). Rats were fed for six weeks. Male rats were introduced to female rats in the 6 th week for mating on proestrous evening. The levels of transforming growth factor β-1 (TGFβ-1) and Insulin like growth factor -1 (IGF-1) were measured at days 6, 8 and 19 of pregnancy.Birth weight, placenta weight and fetal weight (day 19) were decreased in low salt fed rats while placenta weight and fetal weight (Day 19) were increased in high salt fed rats. IGF-1 levels were decreased on days 8 and 19 of pregnancy in low salt fed rats while TGFβ-1 levels were also decreased on days 6, 8 and 19 of pregnancy in the low salt fed rats when compared with control.Growth of low salt offspring’s matched that of controls on day 6 of lactation while the growth of the control and low salt fed rats only reached same values as those of the offspring’s of high salt fed rats on day 15 of lactation. In conclusion,reduced fetal development and low birth weight in low salt fed rats is associated with reduced levels of IGF-1 and TGFβ-1 during pregnancy. Keywords: Salt; growth factors; transforming growth factor beta-1;insulin like growth factor-1; lactation; catch-up growth

High dietary salt ingestion causes elevated blood pressure both in humans and in experimental animals.Following reports that Calcium Channel Blockers may exhibit differences in the response of blood vessels to pressor agents,this study sought to test the effects of amlodipine on blood pressure (BP) and baroreceptor reflex sensitivity (BRS) responsesto high salt ingestion. Three groups of weanling Sprague-Dawley rats i.e. control rats (CR), salt loaded rats (SR) and saltloaded rats concomitantly administered orally with amlodipine (SR+Am) were used. At the end of 6-week experimentalperiod, terminal arterial BP was determined from one femoral artery. BRS was calculated from the change in heart rate perchange in mean arterial BP following bilateral carotid artery occlusion. Plasma sodium and potassium ion concentrationswere also determined. Results show that dietary salt loading in SR significantly increased systolic and diastolic BP and Na+concentration but decreased BRS and K+ concentrations significantly. These changes were abolished in the (SR+Am) rats indicating the ability of amlodipine to ameliorate the increase in blood pressure, reduction in baroreceptor reflex sensitivityand alterations in plasma Na+ and K+ levels that were observed in SD rats fed a high salt diet.

There are not many studies designed to study the relationship between vascular reactivity and salt sensitivity in a black population. Fifty-two hypertensive (HT) and forty-seven age-matched normotensive (NT) Nigerian subjects took part in the study after informed consent was obtained from them. Ethical clearance was obtained from the College of Medicine of the University of Lagos. Vascular hyperreactivity in response to the Cold Pressor Test (CPT) was determined as a change in systolic blood pressure (ΔSBP) or diastolic blood pressure (ΔDBP) ≥ +15mmHg. This was determined before and after salt-loading with 200mmol Na + /day for 5 days. Salt sensitivty was determined as a change in mean arterial blood pressure (ΔMABP) ≥+5mmHg. Salt-loading led to significant increases in SBP among NT (p = 0.03) and among HT (p = 0.0001) subjects; DBP increased significantly only among HT subjects (p = 0.0003). Systolic and diastolic hyperreactivity were higher among HT (49% and 39% respectively) compared to NT (44% and 39% respectively) at baseline. However systolic hyperreactivity (SHP) increased from 44% to 64% after salt-loading among the NT while diastolic hyperreactivity (DHP) reduced from 39% to 36%. Among the HT, both SHP and DHP reduced from 49% to 33% and from 41% to 31% respectively following salt-loading. Salt sensitivity was higher among HT (56%) compared to NT 34%. Salt sensitivity was positively correlated with systolic reactivity before salt (r = 0.33; p 0.05) but negatively correlated with diastolic reactivity before salt (r = -0.38; p < 0.05) and after salt (r = -0.40; p < 0.05) among NT. These results suggest that systolic hyperreactivity may be a significant determinant in the development of salt sensitive hypertension among this population. Keywords: Vascular reactivity, Salt sensitivity hypertension, Blood pressure

Sodium overload, which is present in a high salt diet (HSD), induces hypertension by mechanisms that include change in the shear stress and geometric modifications of the blood vessels. Salt sensitivity exhibits sex difference, which is higher in males when compared with females. This has been attributed to the effect of androgens on blood vessels in males. Therefore, experiments were designed to study the vascular smooth muscle histomorphometry in weanling male rats that were either sham-operated or ochidectomised under (90mg/kg bodyweight ketamine and 10mg/kg bodyweight xylazinei.p) anesthesia, with or without testosterone replacement (TR) (10mg/kg sustanon 250® i.m) once in 3 weeks. They were either placed on a diet with normal 0.3% or high 8% NaCl content for 6 weeks. Histological examination of thoracic aorta and mesenteric artery were carried out with specific dyes; hematoxylin and eosin stain for the cytoplasm and nucleus and Verhoeff – Van Geison and Picro-sirius red stains for elastin and collagen content estimation respectively. Histomorphometric analysis was carried out using a programmed software IMAGE-PRO 3DS 6.1. Tunica media thickness, cross sectional area, elastin and collagen contents of the blood vessels were all significantly elevated (p<0.05) in the rats placed on HSD, while orchidectomy prevented the increase in these parameters but concomitant administration of testosterone restored them to the levels observed in intact rats. Orchidectomy ameliorated vascular hypertrophic effect of a HSD by reducing vascular smooth muscle proliferation and extracellular matrix protein deposition in the blood vessels. Keywords: Orchidectomy, Testosterone, Vascular hypertrophy, Extracellular matrix protein, media thickness, Histomorphometry

Corrigendum to ‘Testosterone relaxes abdominal aorta in male prague–Dawley rats by opening potassium (K+) channel and blockade of calcium (Ca2+) channel’ [Pathophysiology 18 (3) (2011) 247–253] Ahmed Kolade Oloyo a,∗, Olusoga A. Sofola a, Renuka R. Nair b, V.S. Harikrishnan c, Adelaide C. Fernandez c, Chikodi N. Anigbogu a a Department of Physiology, College of Medicine, University of Lagos, Idi – Araba Lagos, Nigeria b Division of Cellular and Molecular Cardiology (DCMC), Sree Chitra Tirunal Institute for Medical Sciences (SCTIMST), Medical College, Trivandrum, Kerala, India c Department of Laboratory Animal Sciences (DLAS), Biomedical Technology (BMT) Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), Poojapurah, Trivandrum, Kerala, India

The effect of sex hormones on vascular reactivity is considered one of the underlying factors contributing to gender differences in cardiovascular functions and diseases. Experiments were designed to investigate the role of androgens in salt-induced hypertension by assessing the relaxation response of isolated aortic rings to acetylcholine and sodium nitroprusside in the presence or absence of l-nitroarginine methyl ester in Sprague–Dawley rats. The rats were either orchidectomized or sham-operated, with or without testosterone replacement, and were placed on a normal or high-salt diet for 6 weeks. The results indicate a significant increase (p < 0.001) in the mean arterial blood pressure of rats on the high-salt diet, when compared with control or orchidectomized rats. Orchidectomy elicited a reduction in mean arterial blood pressure (p < 0.01), while testosterone replacement normalized mean arterial blood pressure to values seen in intact rats on the high-salt diet. The high-salt diet reduced the relaxation response to acetylcholine both in the presence and absence of inhibition of endothelial nitric oxide synthase with l-nitroarginine methyl ester. Bilateral orchidectomy attenuated the impaired endothelial function induced by the high-salt diet in rats, but this was reversed by concomitant administration of testosterone, suggesting a role for androgens in enhancing long-term vascular smooth muscle tone and hence maintenance of high blood pressure in salt-induced hypertension.