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T Hines

Publications and source records attributed to T Hines.

At least 19 recordsLinked to original sources
PubMed2000

Pregnancy alters cardiac receptor afferent discharge in rats.

Reflex effects of cardiac receptor (CR) stimulation are attenuated in pregnant rats. We tested whether CR afferent discharge is reduced during pregnancy by measuring single fiber activity in response to increases in right atrial pressure (RAP) in anesthetized pregnant and virgin rats with sinoaortic denervation. Single fiber activity was isolated from fine filaments of the right cervical vagus nerve. Changes in CR discharge, RAP, and arterial pressure were recorded in response to atrial saline injections (25-300 microl). Resting RAP was similar between groups, and spontaneous CR discharge was similar in pregnant rats (1.95+/-0.21 Hz) and in low-frequency (LF) receptors in virgin rats (1.30+/-0.2 Hz). In virgin, but not pregnant rats, a subset (24%) of CR had higher-frequency (HF) spontaneous discharge (9.91+/-1.19 Hz). During stimulation, the level of RAP above which CR firing increased was significantly higher in pregnant rats, but CR activity was clustered into an LF discharge range. Thus gestation appears to reduce the activity of CR afferents, possibly by increasing stimulus threshold or by selective inactivation of a subset of HF discharging receptors.

Animals↗
PubMed2000

Effect of cardiac receptor stimulation on renal vascular resistance in the pregnant rat.

Stimulation of cardiac receptors (CR) evokes blunted reflex reductions in mean arterial pressure (MAP) in pregnant compared with virgin rats. Because CR-mediated sympathoinhibition has preferential effects on the kidney, we tested whether, during pregnancy, renal vascular resistance (RVR) changes less in response to CR stimulation and investigated possible mechanisms. MAP, right atrial pressure, renal sympathetic nerve activity (RSNA), renal blood flow (RBF), and RVR were measured in anesthetized animals in response to CR stimulation by graded atrial injections of saline. Baseline MAP and RVR and reflex changes in these variables during CR stimulation were reduced in late-pregnant vs. virgin rats (P<0.05). Reflex changes in RSNA were attenuated in pregnant rats, but changes in RBF as a function of RSNA were similar in both groups. ANG II AT(1)-receptor blockade increased basal RBF more in virgin rats (P<0.05), but between-group differences in reflex changes in MAP, RSNA, and RVR were maintained after AT(1) blockade. Thus during CR simulation, reflex changes in RVR were reduced in pregnant versus virgin rats. This difference does not appear to involve differential effects of ANG II.

Angiotensin II↗
PubMed2000

Baroreceptor afferent discharge in the pregnant rat.

Pregnancy is associated with blunted reflex responses to cardiac and arterial baroreceptor stimulation. We tested the hypothesis that arterial baroreceptor afferent discharge is attenuated in response to a pressure stimulus in pregnant rats. Multifiber aortic depressor nerve activity (ADNA), mean arterial pressure (MAP), and heart rate were measured in anesthetized (pentobarbital sodium, 35 mg/kg ip) late-pregnant and virgin rats in response to increases ¿phenylephrine (PE), 1.5-24 microg. kg(-1). min(-1) and 1-16 microg/kg and decreases ¿sodium nitroprusside (SNP), 5-80 microg. kg(-1). min(-1) and 0.05-16 microg/kg in MAP. Resting MAP was lower in pregnant rats, but changes in MAP were similar to those in virgin rats during both PE and SNP administration. ADNA was significantly attenuated in pregnant animals during both PE and SNP infusions (P < 0.05) due to a more rapid adaptation to the pressure stimulus. Bolus drug administration evoked similar changes in MAP and ADNA in both groups; however, the maximum decrease in ADNA was achieved at the lowest dose of SNP in pregnant rats. Thus baroreceptor afferent discharge is attenuated in pregnant rats, and this involves a more rapid adaptation to a pressure stimulus.

Animals↗
PubMed2000

Male entertainment award winners are older than female winners.

It has been said that in the entertainment industry after a certain age women have a harder time being as successful as men. Four analyses of the ages of male and female Oscar winners, Oscar nominees, Emmy winners, and Grammy winners over the past 25 years showed that in all four groups women were, on the average, younger than the men. Two interpretations of these differences are delineated.

Adult↗
PubMed1999

A demonstration of auditory top-down processing.

A simple demonstration of auditory top-down processing is described in which one speech embedded in several others becomes much clearer when participants read a text of the target speech at the same time as they hear it.

Auditory Perception↗
PubMed1997

Nitric oxide mediation of cardiac receptor reflex responses in the pregnant rat.

OBJECTIVES: Our purpose was to determine the contribution of centrally released nitric oxide to baseline sympathetic tone and reflex cardiovascular responses to cardiac stretch in the pregnant rat. STUDY DESIGN: Baseline blood pressure and renal sympathetic nerve activity and reflex changes in these variables in response to intraatrial saline solution injections were measured in anesthetized pregnant (n = 24) and virgin (n = 27) rats before and after bilateral microinjection of L-nitroarginine methyl ester (0.01 to 1 micromol) into the dorsal medulla. Data were analyzed with use of nonparametric analysis of variance. RESULTS: L-Nitroarginine methyl ester microinjection altered basal blood pressure and sympathetic nerve activity (p < 0.05) in virgin but not pregnant rats. L-Nitroarginine methyl ester significantly and equivalently attenuated the reflex sympathoinhibitory and depressor responses to cardiac stretch for 40 minutes in pregnant and virgin animals. CONCLUSION: Central nitric oxide does not modulate basal sympathetic tone in the pregnant rat but is released in the medulla in response to cardiac stretch and plays a role in reflex cardiovascular responses similar to that in virgin rats.

Animals↗
PubMed1996

Proofreaders' decreased Stroop interference.

12 professional proofreaders and 12 control subjects performed a Stroop color-word task. The control subjects showed significantly more Stroop interference than did the proofreaders. It appears that a career in proofreading makes it easier for subjects to ignore the meaning of word stimuli.

Adult↗
PubMed1996

National Hockey League players from North America are more violent than those from Europe.

It is commonly believed by hockey fans that European hockey players rely more on skill while. North American players are more violent. The number of penalty minutes gathered by European and North American players in the National Hockey League's 1995-1996 season was examined. When corrected for the low proportion of European players, North American players had significantly more penalty minutes than European players.

Aggression↗
PubMed1995

Gestational effects on volume-sensitive cardiopulmonary receptor reflexes in the rat.

We tested the hypothesis that augmented reflex sympathoinhibition mediated by volume-sensitive cardiopulmonary (CP) receptors contributes to the vasodilation of pregnancy by comparing responses to acute volume expansion in 21-day-pregnant and age-matched virgin rats (n = 7) that were anesthetized (pentobarbital sodium, 50 mg/kg ip), paralyzed (gallamine triethiodide, 25 mg/kg iv), ventilated, and had undergone bilateral sinoaortic denervation. CP receptors were stimulated with intra-atrial injections of saline (50, 100, 200, and 300 microliter), and the following variables were recorded: 1) mean right atrial pressure (MRAP) to index the afferent stimulus intensity; 2) cell discharge in the nucleus tractus solitarii (NTS), the primary central terminus for CP afferents; and 3) mean arterial pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA) to assess efferent reflex effects. Basal MAP was significantly lower in pregnant (71.5 +/- 3.8 mmHg) than in virgin rats (86.6 +/- 3.1 mmHg), and plasma volume was expanded in the pregnant group (17.6 +/- 1.1 vs. 10.0 +/- 0.7 ml, P < 0.05). Baseline MRAP was similar between groups. Saline injections evoked graded increases in MRAP, which were larger in gravid animals (P < 0.05). Volume injections evoked similar changes in NTS cell discharge between groups, but the responses were nongraded. Despite larger changes in MRAP in gravid rats, reflex effects on RSNA and HR were similar to those in control animals, and effects on MAP were attenuated in the pregnant group. We conclude that larger changes in MRAP in pregnant rats during stimulation of CP receptors are not associated with larger changes in central or efferent components of this reflex.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

A glutathione S-transferase (GST) isozyme from broccoli with significant sequence homology to the mammalian theta-class of GSTs.

A novel glutathione S-transferase (GST) was purified from broccoli (Brassica oleracea var. italica). Partial amino-acid sequencing indicated that the protein shared significant homology with several different plant GSTs from maize, silene, Dianthus, Nicotiana and Triticum, but little homology to yeast (Issatchenkia) GST. One region of the polypeptide near the N-terminal also shared significant homology to a region of rat 5-5, rat 12-12 and human theta-GST (collectively referred to as the theta-GST-class) but little structural homology to the common mammalian cytosolic GSTs (alpha-, mu- or pi-classes). The broccoli GST was retained on a novel membrane based glutathione affinity matrix and displayed activity towards 1-chloro-2,4-dinitro-benzene (CDNB), a general GST substrate, as well as 4-nitrophenethyl bromide, a marker substrate for the theta-class of GSTs. The characteristics of the broccoli GST potentially define it as a member of the theta-class. This is consistent with the view that the theta-class may have arisen prior to the divergence of animals and plants while the mammalian mu-, pi- and alpha-classes evolved after the two kingdoms were established.

Amino Acid Sequence↗
PubMed1994

Effect of autonomic blockade on pressor responses to vasopressin in pregnant rats.

OBJECTIVE: We tested the hypothesis that gestational changes in reflex neural control of the heart and vasculature contribute to altered cardiovascular responses to vasopressin during pregnancy. STUDY DESIGN: Changes in mean arterial pressure, cardiac output, total peripheral resistance, and heart rate were measured in response to constant infusion of arginine vasopressin (0.15 to 2.5 mU/kg/min) in conscious pregnant and virgin rats (n = 9) with total autonomic blockade plus restoration of baseline hemodynamics by norepinephrine infusion. RESULTS: Resting cardiac output was 40% higher and total peripheral resistance 30% lower in pregnant animals (p < 0.01). Constant infusion of arginine vasopressin evoked equivalent changes in mean arterial pressure in both groups, but the respective contributions of cardiac output and total peripheral resistance to mean arterial pressure differed between groups. Cardiac output was unchanged and the increase in total peripheral resistance was significantly blunted in pregnant vs virgin rats during arginine vasopressin infusion. Control data in nonblocked revealed similar pressor responses to arginine vasopressin in gravid compared with virgin rats but no differences in the contributions of cardiac output and total peripheral resistance to the change in mean arterial pressure. CONCLUSION: These findings suggest that neural modulation of arginine vasopressin-induced hypertension is altered during pregnancy and are consistent with a reduction in intrinsic vascular sensitivity to arginine vasopressin during gestation.

Animals↗
PubMed1994

Responses of neurons in the nucleus tractus solitarius to stimulation of heart and lung receptors in the rat.

To characterize central integration of reflex responses to stimulation of mechanically and chemically sensitive receptors in the heart and lung, male rats (350 to 425 g) were anesthetized (pentobarbital, 50 mg/kg IP) and paralyzed (gallamine triethiodide, 25 mg/kg IV) and then they underwent bilateral sinoaortic denervation. Extracellular activity of neurons in the nucleus tractus solitarius (NTS) was recorded in response to bolus intra-atrial saline (50, 100, 200, or 300 microL) or phenylbiguanide (PBG, 16 micrograms/kg in 100 microL) administered in random sequence. Changes in mean arterial pressure (MAP), mean right atrial pressure, and right atrial systolic pressure (RASP) were measured as correlates of stimulus intensity, and heart rate (HR) and renal sympathetic nerve activity (RSNA) were used to assess efferent reflex effects of cardiac and pulmonary receptor stimulation. NTS neurons with possible afferent input from stretch and chemically sensitive receptors were identified by an excitatory evoked response to electrical stimulation of the ipsilateral vagus nerve (1 Hz, 500 microA, 1-millisecond duration). Thirty-eight vagus nerve-evoked NTS units with onset latencies of 25.3 +/- 0.9 milliseconds displayed excitatory or inhibitory responses to saline or PBG injections or to both interventions. Saline administration elicited volume-dependent transient increases in MAP and RASP, which were followed by reflex decreases in MAP, HR, and RSNA. PBG injections also evoked hypotension, bradycardia, and sympathoinhibition.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

High resolution 2-D peptide mapping with subsequent analysis of peptides by microsequencing or lectin binding directly from PVDF membrane blots.

Peptide mapping is a technique that is frequently used to characterize proteins. Typically, the method involves the cleavage of proteins in solution or in a gel with the subsequent separation of the peptide fragments on a 1-D SDS PAGE gel. Electrophoretic peptide maps are often used to compare homologous proteins from related organisms to derive evolutionary relationships. Other applications of peptide mapping include immunoblotting studies of selected proteins. Two-dimensional peptide mapping, a less common technique, has traditionally involved a combination of thin layer or paper chromatography and electrophoresis. Amino acid sequencing of peptides that were separated using this method and then subsequently blotted to PVDF membrane was reported recently. However, the resolution achieved with these methods is far below that which can be achieved with conventional 2-D electrophoresis of proteins in polyacrylamide gels. This report describes an electrophoretic system for the high resolution 2-D separation of peptides in gels with subsequent blotting to a novel cationic PVDF membrane, Immobilon-CD, and microsequencing directly from the 2-D blot. In addition, the high resolution peptide maps can be further analyzed by techniques such as lectin probing to determine post-translational modifications.

Amino Acid Sequence↗
PubMed1993

Total autonomic blockade eliminates the attenuated pressor response to angiotensin II in pregnant rats.

Pressor responses to angiotensin II (ANG II) are markedly attenuated in reflex-intact pregnant animals, a phenomenon widely attributed to intrinsic changes in vascular reactivity. To test the hypothesis that gestational augmentation of neural reflex activity contributes importantly to this phenomenon, changes in mean arterial pressure (MAP), cardiac output (CO), and total peripheral resistance (TPR) were compared during constant infusion (25-400 ng.kg-1.min-1) of ANG II in conscious virgin and pregnant rats, using a model of total autonomic blockade (chlorisondamine chloride and methscopolamine bromide), with restoration of baseline hemodynamics by infusion of norepinephrine. Basal CO was higher and TPR lower in pregnant (CO 121.8 +/- 3.8 ml/min; TPR 0.78 +/- 0.04 mmHg.ml-1.min) compared with virgin (CO 95.9 +/- 3.9 ml/min; TPR 1.05 +/- 0.08 mmHg.ml-1.min) rats (P < 0.005). Pressor responses to ANG II were similar in both groups of reflex-blocked animals due to comparable changes in TPR and CO (not significant by repeated-measures analysis of variance). Other experiments demonstrated that changes in MAP after bolus administration of ANG II did not differ in areflexic virgin and gravid rats. Thus in the absence of autonomic control ANG II has similar effects on systemic resistance in pregnant and nonpregnant rats, suggesting that reflex neural mechanisms contribute significantly to gestational changes in pressor responsiveness. These data further suggest that pregnancy is not accompanied by a generalized decrease in vascular reactivity to all pressor agents.

Angiotensin II↗
PubMed1992

Pressor effect of posterior hypothalamic stimulation is enhanced in pregnant rats.

In contrast to the attenuated pressor response to intravenous angiotensin II (ANG II) in rat pregnancy, the response to intracerebroventricular ANG II is not blunted. To test whether this difference was due to enhanced effects of sympathetic nervous system activation, blood pressure, heart rate, and renal and mesenteric blood flow were measured in conscious term-pregnant and age-matched virgin rats during electrical stimulation of the posterior hypothalamus and during intravenous infusion of norepinephrine (NE). The pressor responses to endogenous NE release by hypothalamic stimulation were significantly greater (P less than 0.05) in pregnant rats at 10, 15 and 20 Hz. In contrast, the pressor response to exogenous NE was significantly blunted in gravid animals. These differences were not associated with significant differences in renal or mesenteric vascular resistance changes. We conclude that the lack of an attenuated response to intracerebroventricular ANG II in the pregnant rat can be explained in part by an enhanced pressor effect of sympathetic nervous system activation.

Animals↗
PubMed1992

Effect of sinoaortic denervation on pressor responses in pregnant rats.

We tested the hypothesis that augmented arterial baroreflex activity contributes to attenuation of pressor responses in intact pregnant animals by comparing changes in blood pressure and heart rate during infusions of angiotensin II, phenylephrine, and vasopressin in chronically instrumented pregnant and virgin rats approximately 5 wk after sinoaortic denervation (SAD) or sham surgery. Baseline mean arterial pressure was significantly lower in pregnant animals in both the sham-operated (pregnant 91.7 +/- 1.7 mmHg, virgin 103.7 +/- 2.5 mmHg) and SAD states (pregnant 107.3 +/- 4.0 mmHg, virgin 114.1 +/- 4.0 mmHg). Pressor responses to all three agents were significantly blunted in pregnant animals compared with similarly treated virgins, with the magnitude of attenuation similar in both sham and SAD states. Heart rate decreased similarly in reflex-intact pregnant and virgin animals during pressor infusions. These findings suggest that attenuated pressor responses in the pregnant rat are due primarily to mechanisms other than augmentation of arterial baroreflex activity and are consistent with a generalized reduction in vascular sensitivity during gestation.

Angiotensin II↗