Computerized image-analysis techniques have been employed to examine the sarcomere dynamics of isolated mammalian cardiac myocytes. The cells were prepared by perfusion adult rabbit hearts with hyaluronidase-collagenase solutions; they exhibited phasic contractions in presence 10(-6) M Ca2+. dissociated visualized phase microscopy and a video camera interfaced minicomputer. Digitized cell images processed an algorithm utilizing signal averaging contrast enhancement yield data showing...

Adiponectin is an adipocyte-derived peptide hormone involved in energy homeostasis and the pathogenesis of obesity, including hypertension. Area postrema (AP) lacks a blood–brain barrier critical homeostatic integration center for humoral neural signals. Here we investigate role AP adiponectin signaling. We show that rat expresses AdipoR1 AdipoR2 receptor mRNA. used current-clamp electrophysiology to whether influenced membrane properties neurons found ∼60% tested were sensitive adiponectin....

The mechanisms through which circulating ghrelin relays hunger signals to the CNS are not yet fully understood. In this study, we have examined potential role of subfornical organ (SFO), a circumventricular structure that lacks normal blood-brain barrier, as site in acts influence hypothalamic centers controlling food intake. We report increased intracellular calcium concentrations 28% (12 43) dissociated SFO neurons and expresses mRNA for growth hormone secretagogue receptor. Whole-cell...

We have employed microarray technology using Affymetrix 230 2.0 genome chips to initially catalog the transcriptome of subfornical organ (SFO) under control conditions and also evaluate changes (common differential) in gene expression induced by challenges fluid food deprivation. identified a total 17,293 genes tagged as present one our three experimental conditions, transcripts, which were then used basis for further filtering statistical analysis. In total, 46 was changed SFO following...

Adiponectin is an adipocyte derived hormone which acts in the brain to modulate energy homeostasis and autonomic function. The paraventricular nucleus of hypothalamus (PVN) plays a key role controlling pituitary secretion has been suggested be central target for adiponectin actions. A number hormones produced by PVN neurons have implicated regulation including oxytocin, corticotropin releasing thyrotropin hormone. In present study we investigated excitability magnocellular (MNC--oxytocin or...

The subfornical organ (SFO) is a sensory circumventricular organ, lacking blood-brain barrier. It well-recognized as key center for detection and integration of osmotic, ionic hormonal signals maintenance hydromineral balance cardiovascular regulation. Recently, the SFO has also been recognized circulating satiety regulation energy balance. Neuropeptide Y (NPY) multifunctional neuropeptide, with effects on balance, tone other aspects homeostasis. Interestingly, despite overlap function...

Ghrelin, a peptide hormone secreted from the stomach, is known to have potent appetite-stimulating activity. Recently, it has been shown that area postrema (AP), caudal brain stem center lacks blood-brain barrier, key site of activity for ghrelin in stimulating appetite and regulating pancreatic protein secretion. In this study, we examined ability regulate electrical neurons using patch-clamp electrophysiology. Using current-clamp configuration, found at concentration 10 nM, caused...

Ghrelin, a peptide hormone secreted by the stomach, has been shown to regulate energy homeostasis modulating electrical activity of neurons in central nervous system (CNS). Like many circulating satiety signals, ghrelin is and unable cross blood-brain barrier without transport mechanism. In this review, we address notion that arcuate nucleus hypothalamus only site CNS detects trigger orexigenic responses. We consider roles specialized group structures called sensory circumventricular organs...

Abstract As Purkinje neurons mature during postnatal development, they change from electrically quiescent to active and exhibit high frequency spontaneous action potentials. This in electrical activity is determined by both alteration ion channel expression the acquisition of synaptic input. To gain a better understanding development intrinsic properties these neurons, acutely isolated mice aged day 4 (P4) P18 were examined. included recording potential frequency, threshold, height slope,...

We investigated the mechanisms responsible for increased blood pressure and sympathetic nerve activity (SNA) caused by 2-3 days dehydration (DH) both in vivo situ preparations. In euhydrated (EH) rats, systemic application of AT(1) receptor antagonist Losartan subsequent pre-collicular transection (to remove hypothalamus) significantly reduced thoracic (t)SNA. contrast, DH Losartan, followed pontine transections, failed to reduce tSNA, whereas at medulla-spinal cord junction massively tSNA....

Insulin plays a crucial role in the regulation of energy balance. Within central nervous system, hypothalamic nuclei such as arcuate and ventromedial are targets insulin; however, insulin may only access these after transport across blood-brain barrier. Neurons subfornical organ not protected by barrier can rapidly detect respond to circulating hormones leptin ghrelin. Moreover, neurons form synaptic connections with control centers that regulate balance, including dorsomedial nuclei....

The area postrema (AP) is a sensory circumventricular organ characterized by extensive fenestrated vasculature and neurons which are capable of detecting circulating signals osmotic, cardiovascular, immune metabolic status. AP can communicate these messages via efferent projections to brainstem hypothalamic structures that able orchestrate an appropriate response. We have used microarrays profile the transcriptome in Sprague-Dawley (SD) Wistar-Kyoto rat present here comprehensive catalogue...

Abstract Cerebellar Purkinje neurons in vivo exhibit high frequency and multi‐spike action potentials with transient (I NaT ), resurgent NaR ) persistent NaP Na + currents arising from voltage‐gated channels, which play important roles shaping the electrical activity of these cells. However, little is known about channel expression cultured despite use vitro approaches to study Therefore, GFP‐expressing isolated transgenic mice were analysed after four weeks culture, when, coincident...

Previous work has demonstrated that subfornical organ neurons exhibit spontaneous action potentials interspersed with periods of membrane potential oscillation. We used whole cell patch clamp recording to investigate properties these oscillations. The amplitude, but not the frequency, oscillations exhibited voltage dependence. were unaffected by application blockers for gamma-amino-n-butyric acid type A (GABA(A)) and glutamate receptors, nor they affected Cd2+ block Ca2+ channels, or Cs+...

Prokineticin 2 (PK2) is a neuropeptide that acts as signaling molecule regulating circadian rhythms in mammals. We have previously reported PK2 actions on subfornical organ (SFO) neurons, identifying this circumventricular target at which to influence autonomic control (Cottrell GT, and Ferguson AV. J. Neurosci. 24: 2375-2379, 2004). In study, we examined the cellular mechanisms by increases excitability of SFO neurons. Whole cell patch recordings from dissociated rat neurons demonstrated...

Early postnatal overnutrition in humans is associated with long-term negative outcomes including obesity, increased risk of type-II diabetes, and cardiovascular disease. Hypothalamic neurons from rodents exposed to early show altered expression satiety signals receptors, exhibit responses many signals, suggesting a hypothalamic link between development these sequelae. Importantly, several nuclei receive information regarding circulating hormones (such as insulin, leptin ghrelin) the...