Sympathetic nerve fibers to thyroid blood vessels contain both norepinephrine (NE) and neuropeptide Y (NPY). To assess the involvement of endogenous NPY in the sympathetic neural control of thyroid blood flow, appropriate doses of a selective NPY antagonist, alpha-trinositol, and an NPY antiserum (NPY-AS) were used during cervical sympathetic trunk ...

Injection of water into a lobar bronchus stimulates airway C-fibers and rapidly adapting receptors and evokes airway defense reflexes. To determine whether this stimulus also evokes a reflex increase in bronchial blood flow (Qbr), we injected 1-2 ml of water into a lobar bronchus in anesthetized dogs. Injection decreased arterial ...

Stimulation of cerebrovascular parasympathetic nerves markedly increases cortical blood flow. Nitric oxide (NO) or a NO-containing compound is present in these nerves and may therefore, upon release, be partly responsible for the flow increase. In addition, transmitters released from the nerves may cause synthesis and release of this compound from ...

The integrity of the blood supply to three equal segments of a nerve was determined, after the nerve was cut and folded but with its epineurial vasculature remaining intact. A 7.5-cm length of the rabbit sciatic nerve was elevated on a single pedicle. The epineurium was slit longitudinally, and the ...

1. The effect of the calcitonin gene-related peptide antagonist (CGRP8-37, 400 nmol kg-1, i.v.) on the increased blood flow induced by calcitonin gene related peptide (CGRP), vasodilator prostaglandins, and topical capsaicin was measured with a laser Doppler blood flow meter in rat abdominal skin. 2. The saphenous nerve was electrically ...

The sacral anterior nerve roots were stimulated in a conscious female paraplegic by means of an intradural implanted Finetech/Brindley stimulator activated by inductive radio signals. Changes in vaginal blood flow were monitored by a photoplethysmograph. Stimulating S2 and S3 (but not S4) caused significant increases in vaginal pulse amplitude indicating ...

The acute influence of exogenous transmitters and sympathetic nerve stimulation on the composition of blood cells in the splenic vein in relation to the splenic vascular effects was investigated in anaesthetized pigs. Intra arterial bolus injections of 720 pmol neuropeptide Y (NPY), 4.9 nmol noradrenaline (NA) and 20 nmol alpha,beta-methylene ...

The aim of this study was to investigate the blood flow in the adrenal cortex of the rat. Relative changes in the adrenal cortical blood flow were continuously measured by Laser Doppler flowmetry in 33 chloralose-anaesthetized artificially ventilated rats during electrical stimulation (1 ms, 5 V) of the left great ...

Experiments were performed to investigate the presence and nature of beta-adrenoceptors in blood vessels supplying the posterior capsule of the rabbit knee joint. Electrical stimulation of the posterior articular nerve (PAN) and close intra-arterial injection of adrenaline produced vasoconstriction which reversed to vasodilatation with administration of the alpha-adrenoceptor antagonist phenoxybenzamine. ...

A model was developed using pentobarbital anesthetized pigs to study bilateral blood flow changes in the nasal mucosa by flow-probes on both sphenopalatine arteries. Unilateral mechanical stimulation of the nasal mucosa for 10s as well as close intra-arterial capsaicin infusion induced bilateral vasodilation. The magnitude of the vasodilator responses were ...

Although hormonal regulation of blood calcium homeostasis has been intensively investigated in the peripheral organs, the involvement of the central nervous system in calcium regulation is still poorly understood. In the present study, we found that (1) bilateral lesions of the ventromedial nucleus of the hypothalamus (VMH), but not those ...

We evaluated the effects of Ca2+ entry blockers, nilvadipine and flunarizine, on microcirculatory disorders of the inner ear and on blood flow in the inner ear of rats. Under sodium pentobarbital anesthesia, the middle ear was opened by a ventrolateral approach. A green light (wave length 540 nm) was applied ...

In conscious pigs, arteriovenous anastomoses (AVAs) are in a constricted state so that < 5% of intra-atrially injected radioactive (15-microns-diam) microspheres are shunted to the lungs. Many of the anesthetic regimens frequently used in cardiovascular research dilate AVAs, thereby greatly increasing the percentage of microspheres reaching the lungs. This may ...

Impairment of microcirculation of the facial nerves is considered to play an important role in etiology of facial palsy, and the main emphasis of the conservative treatment is aimed at circulatory improvement. Therefore, at the pain clinic, improved blood flow to the facial nerve by chemical blockage of cervical sympathetic ...

Intrascapular brown adipose tissue temperature (TIBAT) and capillary blood flow along with colonic (Tc) and tail (Tt) temperatures as well as blood pressure and heart rate responses were measured simultaneously in groups of age-matched, anesthetised, sham control and IBAT-denervated Long-Evans rats following VMH electrical stimulation. Unilateral VMH electrical stimulation (0.5 ...

A noninvasive strain-gauge method of measuring blood flow in the digit was used to assess the influence of the sympathetic system in the digit. The sympathetic system was stimulated by the sudden application of ice to the neck, thus avoiding in the hand local reflexes and responses to cold. Seventeen ...

A new model is described for monitoring nerve blood flow during expansion by laser Doppler flowmetry. Rabbit sciatic nerve is gradually expanded with a custom-made spherical expander, while nerve blood flow is monitored by laser Doppler flow output. This model provides a valid method of controlling nerve blood flow during ...

A 51-year-old male with a huge chondrosarcoma received subarachnoid dorsal root blocks with 10% phenol in glycerine to treat severe pain along the left leg. The dermatomes below the Th9 lost all somatic sensation on the left side after the nerve blocks, but the patient was not completely relieved from ...

The centromedian-parafascicular complex (CMPf) of the intralaminar thalamus was stimulated in anesthetized, ventilated rats, and cerebral cortical perfusion was continuously measured using laser Doppler flowmetry. Stimulation led to a frequency- and intensity-dependent increase in cortical perfusion (vasodilatation). The maximum response was seen at a rate of 200/s, and studied at ...

Migraine is a neurovascular reaction to sudden changes in the internal or external environment. Each individual has a hereditary "migrainous threshold," with the degree of susceptibility depending on the balance between excitation and inhibition at various levels of the nervous system. The mechanism of migraine has been presented as an ...

Stimulation of alpha 2 adrenergic receptors inhibits colonic motility and may constrict some peripheral vascular beds. Endotoxemia elicits release of sympathetic neurotransmitters and increases sympathetic nerve activity, which may result in stimulation of alpha 2 adrenergic receptors. The objective of this study was to determine whether blockade of alpha 2 ...

The head is innervated by neurons with cell bodies in the trigeminal ganglion that contain both calcitonin gene-related peptide (CGRP) and substance P. The CGRP-containing neurons preferentially innervate the cerebral vessels and when activated produce both an increase in blood flow and local release of CGRP. In this study, the ...

Potassium ion-containing solutions have been shown to initially excite then depress intradental nerve activity (INA) when applied into deep dentinal cavities. The INA reflects activity originating in intradental A fibers. Application of KCl to deep dentinal cavities also induces an increase in pulpal blood flow (PBF). Capsaicin is known to ...

The effect of chronic sympathetic and possibly sensory denervation on flow-induced changes in smooth muscle tone was examined in a branch of the rabbit ear artery (200-400 microns ID). The superior cervical ganglion and 1-cm portions of the greater and anterior auricular nerves were removed from 4-wk-old rabbits while under ...

Functional studies have yet to be undertaken to establish which brain region subserves the parasympathetic regulation of the cerebral circulation. Using 31 anesthetized rats with precluded cervical sympathetic trunks, we therefore attempted to perform chemical stimulation of the greater petrosal nerve (GPN) cell group, which is a subgroup of the ...

Changes of acetylcholinesterase activity in the blood and different organs of the rat following intoxication with sarin, soman, VX and 2-dimethylamino-ethyl-(dimethylamido)phosphonofluoridate (GV) in doses of approximately 2 x LD50 (i.m.) were obtained from literature data and by experiment. The time course of acetylcholinesterase inhibition in the blood, regions of brain ...

Colour Doppler imaging (CDI) is an ultrasonic method for qualitatively and quantitatively assessing blood flow. Recently this technique has been adapted for investigation of the orbital, optic nerve and ocular vasculature. We discuss the history, principles and methodology of this examination technique for ophthalmology. Also described are normal haemodynamic characteristics ...

Radiolabelled microspheres were used to measure blood flow of structures in and around the rabbit knee joint and to determine the effect of electrical stimulation of the posterior articular nerve (PAN) supplying the knee. Surgical exposure of the posterior aspect of the knee joint 'capsule' and section of PAN resulted ...

The contribution of neurotransmitters known to be present in the cervical sympathetic nervous system to cerebral autoregulation was evaluated in the anaesthetised cat using a continuous measurement of cerebral cortical perfusion with laser Doppler flowmetry and an in vitro pial vessel preparation. Autoregulation was tested by venesection and fluid administration ...

The effect of sympathetic nerve stimulation and topical application of substance P and calcitonin gene-related peptide on the blood flow of the exposed rat knee joint capsule was investigated. The responses of normal animals were compared to those of animals with acutely inflamed joints induced by intra-articular injection of 2% ...

This study was undertaken to clarify the mechanism of orthostatic hypotension, one of the side effects frequently encountered after administration of levodopa (L-dopa). Muscle sympathetic nerve activity (MSNA) was measured concomitantly with blood pressure (BP), heart rate (HR) and calf blood flow (calf BF). The responses of these variables to ...

For determining the effect of the activation of the central cholinergic system on the sympathetic nervous system, we measured muscle sympathetic nerve activity (MSNA) together with heart rate and blood pressure before and after an intravenous injection of metoclopramide. Immediately after metoclopramide injection, short-term increases in MSNA and heart rate ...

Compression of the spinal nerve roots may occur clinically at multiple levels at the same time; however, the basic pathophysiology of multi-level compression is largely unknown. In this study, the intraneural blood flow was analyzed continuously in the uncompressed segment between two compression balloons, with a pig used as an ...

Both clinical and physiological consideration of migraine suggests that the pathophysiology of the syndrome is intimately linked to the trigeminal innervation of the cranial vessels, the trigeminovascular system. Studies were conducted in cats and humans to examine the interaction of these systems with the effective acute antimigraine drugs dihydroergotamine and ...

Vagal and sympathetic nervous activities in the rabbit were recorded while vertebral blood flow was partially blocked by the injection of adenosine 5'-diphosphate (ADP; platelet aggregator). When a small dose of ADP (0.2 mg/kg) was administered into a unilateral vertebral artery, sympathetic nerve (SN) activity increased, and its magnitude was ...

Intrinsic mechanisms of vasodilatation may prevent injury-related ischemia in peripheral nerve endoneurium. We examined local perfusion up to 10 days following local crush, partial injury or simple exposure of the rat sciatic nerve. By employing epineurial hCGRP(8-37), a receptor antagonist of CGRP, and serial hydrogen clearance measurements, we estimated the ...

Previous studies of the sympathetic nerve supply of the rat mandibular incisor pulp have shown conflicting results. Here, the neurovascular control of the rat lower incisor pulp was investigated by stimulating the tooth crown and the cervical sympathetic trunk electrically and monitoring blood-flow changes in the pulp by laser Doppler ...

In 15 subjects, laser-Doppler flowmetry (LDF) was used to investigate whether the nervous control of pulpal blood flow (PBF) is affected by three tests known to excite the sympathetic nervous system. For comparison, skin blood flow was similarly recorded. Dynamic exercise (bicycle ergometer, 5 min, 90-100 W) in eight subjects ...

The effects of hypercapnia and hypoxia on two local cerebral blood flows in the parietal cortex (PC-BF) and rostral ventrolateral medulla (RVLM-BF) were examined using laser Doppler flowmetry in anesthetized rats. Hypercapnia for 45 s duration at the end-tidal CO2 between 5% and 10%, induced by increasing inspiratory CO2, increased ...

The i.v. 48 hour (and 7 day) LD50 and the minimum lethal dose (MLD) of ricin in male New Zealand White rabbits has been determined by the Up and Down procedure. A MLD and a toxic sub-lethal dose (TSD) lowered blood pressure after a 12 hour or greater lag period, ...

Adenosine participates in the coupling of cerebral blood flow to oxygen consumption in the brain during such stimuli as hypoxia, ischemia, and seizures. It has been suggested that it also participates in the regulation of cerebral blood flow during somatosensory stimulation, a condition during which cerebral blood flow and oxygen ...

We review mainly recent studies on vasodilative regulation of cortex and hippocampus by central cholinergic nerves originating in the basal forebrain. We also briefly review the influence of other central noradrenergic fibers originating in the locus ceruleus, serotonergic fibers originating in the dorsal raphe nucleus, dopaminergic fibers originating in the ...

The effects of thyrotropin-releasing hormone (TRH) on regional blood flows were studied in urethane-anaesthetized rabbits. Experiments were performed both with and without adrenergic antagonist pretreatment. The tracer microsphere method was used to measure blood flow. TRH (0.1 mg kg-1) caused an increase in mean arterial blood pressure (MAP) from 9.8 ...

Laser Doppler flowmetry (LDF) is a technique that measures relative average velocity, number and flux (number times velocity) of red blood cells in a tissue. In this paper, we demonstrate its application in the optic nerve head tissue, describe the laser delivery and light scattering detection schemes and investigate the ...

1. The effect of endothelin-1 on the release of adrenal catecholamines was examined in anaesthetized dogs. 2. Splanchnic nerve stimulation (SNS) at 1 and 3 Hz was applied before and after the intravenous injection of endothelin-1. 3. Endothelin-1 (0.1 and 0.3 micrograms/kg) significantly enhanced the release of adrenal catecholamines induced ...

The microinjection of neuropeptide Y (NPY) 0.75 and 1.5 micrograms into A1 noradrenergic nucleus of cats produced dose-dependent falls in mean arterial blood pressure of 2.0 +/- 0.6 and 4.9 +/- 2.4 kPa, respectively. NPY microinjection (1.5 micrograms) also produced marked decreases in noradrenaline (5 +/- 4 pmol.ml-1) and adrenaline ...

Changes in acetylcholinesterase activity in blood and some organs of rats after intoxication with sarin, soman, VX, and 2-dimethylaminoethyl-(dimethylamido)-phosphonofluoridate (GV), in doses of roughly 2 x LD50 given intramuscularly, were obtained from published data and by experiment. The time course of inhibition of acetylcholinesterase in blood, regions of brain, and ...

The local influence of sympathetic stimulation on the cerebral circulation during acute hypertension was investigated in anesthetized rats. From initial studies, intravenously administered angiotensin II was selected as the pressor agent. Local cerebral blood flow was measured with [14C]iodoantipyrine autoradiography during 1) unilateral electrical stimulation of the superior cervical ganglion ...

With combined microdialysis and hydrogen clearance techniques for simultaneous local delivery of drugs and blood-flow measurement in the rat hindlimb sensory-motor cortex, we examined the role of nitric oxide in cerebral blood-flow regulation during sciatic nerve stimulation. Infusion of 1 mM nitric oxide synthase antagonist, N eta-nitro-L-arginine methyl ester (L-NAME), ...

Somato-parasympathetic reflexive vasodilatation elicited by activation of the nociceptors in the oro-facial areas of the cat was investigated. Changes in lower lip blood flow monitored by a laser Doppler flowmeter took place in pentobarbital-anesthetized and artificially respirated cats. Pinch and heat stimulation of the oro-facial areas evoked a blood flow ...