Tachykinins increase [3H]acetylcholine release in mouse striatum through multiple receptor subtypes.

Tachykinins have been suggested to play a significant role in the mammalian striatum, at least in part by the control of acetylcholine release from cholinergic interneurons. In the present study, we have examined the ability of known tachykinin agonists and antagonists to modulate the activity of these interneurons in mouse striatal slices. Using whole-cell patch-clamp recordings, the selective neurokinin-1, neurokinin-2 and neurokinin-3 receptor agonists [sar9,Met(O2)11]substance P, [beta-ala8]neurokinin A(4-10) and senktide each produced a dose-dependent depolarization of visually identified cholinergic interneurons that was retained under conditions designed to interrupt synaptic transmission.

Detection of static and dynamic components of mechanical allodynia in rat models of neuropathic pain: are they signalled by distinct primary sensory neurones?

In the present study, chronic constrictive injury (CCI model) of the sciatic nerve or tight ligation of L5 and L6 spinal nerves (Chung model) produced both dynamic and static components of mechanical allodynia in rats. The two responses were detected, respectively, by lightly stroking the hind paw with cotton wool or application of pressure using von Frey hairs. Animals with spinal nerve ligation developed both types of responses at a faster rate compared to animals with the CCI.

Characterisation using microphysiometry of CRF receptor pharmacology.

We have assessed the utility of the Cytosensor microphysiometer for studying the pharmacology of recombinant CRF receptors. Chinese hamster ovary cells stably expressing the human CRF1 or CRF2 receptor were perfused in the Cytosensor with bicarbonate-free Hams F12 (pH 7.4) containing 0.

Synthesis and biological evaluation of conformationally restricted Gabapentin analogues.

A series of conformationally restricted Gabapentin analogues has been synthesised. The pyrrolidine analogue (R)-2-Aza-spiro[4.5]decane-4-carboxylic acid hydrochloride (3a) had an IC50 of 120 nM, similar to that of Gabapentin (IC50 = 140 nM), at the Gabapentin binding site on the alpha2delta subunit of a calcium channel.

Serotonin depolarizes hippocampal interneurones in the rat stratum oriens by interaction with 5HT2 receptors.

Patch-clamp recording techniques were used to examine the effect of serotonin (5HT) upon interneurones contained in the stratum oriens layer of hippocampal slices. Bath application of 1-20 microM 5HT depolarized neurones by the induction of an inward current at -60 mV. This inward current was Na+-dependent in nature, was mimicked by the 5HT2 receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and was inhibited by pre-incubation with the 5HT2 receptor antagonist ritanserin.

Bombesin-like peptides depolarize rat hippocampal interneurones through interaction with subtype 2 bombesin receptors.

1. Whole-cell patch-clamp recordings were made from visually identified hippocampal interneurones in slices of rat brain tissue in vitro. Bath application of the bombesin-like neuropeptides gastrin-releasing peptide (GRP) or neuromedin B (NMB) produced a large membrane depolarization that was blocked by pre-incubation with the subtype 2 bombesin (BB2) receptor antagonist [D-Phe6, Des-Met14]bombesin-(6-14)ethyl amide.

Bombesin receptors inhibit G protein-coupled inwardly rectifying K+ channels expressed in Xenopus oocytes through a protein kinase C-dependent pathway.

Although activation of G protein-coupled inward rectifying K+ (GIRK) channels by Gi/Go-coupled receptors has been shown to be important in postsynaptic inhibition in the central nervous system, there is also evidence to suggest that inhibition of GIRK channels by Gq-coupled receptors is involved in postsynaptic excitation. In the present study we addressed whether the Gq-coupled receptors of the bombesin family can couple to GIRK channels and examined the mechanism by which this process occurs. Different combinations of GIRK channel subunits (Kir3.

Gabapentin and pregabalin, but not morphine and amitriptyline, block both static and dynamic components of mechanical allodynia induced by streptozocin in the rat.

A single injection of streptozocin (50 mg/kg, i.p.) led to the development of static and dynamic allodynia in the rat.

Enadoline, a selective kappa-opioid receptor agonist shows potent antihyperalgesic and antiallodynic actions in a rat model of surgical pain.

Enadoline is a highly selective and potent kappa-opioid receptor agonist. This report describes and compares the activities of enadoline and morphine in a rat model of postoperative pain. A 1 cm incision through the muscle and skin of the plantar surface of the right hind paw induced thermal hyperalgesia as well as static and dynamic allodynia lasting at least 2 days.

Glucose-receptive neurones in the rat ventromedial hypothalamus express KATP channels composed of Kir6.1 and SUR1 subunits.

1. Patch-clamp recordings were made from rat ventromedial hypothalamic neurones in slices of brain tissue in vitro. In cell-attached recordings, removal of extracellular glucose or metabolic inhibition with sodium azide reduced the firing rate of a subpopulation of cells through the activation of a 65 pS channel that was blocked by the sulphonylureas tolbutamide and glibenclamide.

A new method for the rapid and long term growth of human neural precursor cells.

A reliable source of human neural tissue would be of immense practical value to both neuroscientists and clinical neural transplantation trials. In this study, human precursor cells were isolated from the developing human cortex and, in the presence of both epidermal and fibroblast growth factor-2, grew in culture as sphere shaped clusters. Using traditional passaging techniques and culture mediums the rate of growth was extremely slow, and only a 12-fold expansion in total cell number could be achieved.

PD 176252--the first high affinity non-peptide gastrin-releasing peptide (BB2) receptor antagonist.

In this paper we describe the development of a novel series of non-peptide, "balanced" neuromedin-B preferring (BB1)/gastrin-releasing peptide preferring (BB2) receptor ligands as exemplified by PD 176252. PD 176252, which exhibits nanomolar affinity for both the BB1 (Ki = 0.15 nM) and BB2 (Ki = 1.

Activation of the cloned human NK3 receptor in Chinese Hamster Ovary cells characterized by the cellular acidification response using the Cytosensor microphysiometer.

1. The aim of the present study was to validate the Cytosensor microphysiometer, a novel system that measures the extracellular acidification rate as a reliable index of the integrated functional response to receptor activation, as a method for studying NK3 receptor pharmacology, and then to use this system to assess the functional activity of novel compounds at this receptor. 2.

Identification of nociceptin in human cerebrospinal fluid: comparison of levels in pain and non-pain states.

We have measured plasma and cerebrospinal fluid (CSF) concentrations of nociceptin, the endogenous agonist of the orphan opioid receptor-like receptor (ORL-1). We studied two groups of ten patients presenting for elective Caesarean section (Group E) or in established labour and requiring combined spinal epidural anaesthesia for pain relief (Group L). Nociceptin was identified in all CSF samples with mean +/- SD concentrations of 52.

Characterization of the mechanism of action of tachykinins in rat striatal cholinergic interneurons.

The mechanism by which substance P depolarizes cholinergic interneurons in the rat striatum was studied using whole-cell recording techniques. In all cases the effects of substance P were mimicked by the neurokinin1 receptor agonist [Sar9, Met(O2)11] substance P and were antagonized by the neurokinin1 receptor antagonist SR140333. [Sar9, Met(O2)11] substance P was found to depolarize cholinergic interneurons by the induction of a calcium-activated inward current at -60 mV.

Cloning and deletion mutagenesis of the alpha2 delta calcium channel subunit from porcine cerebral cortex. Expression of a soluble form of the protein that retains [3H]gabapentin binding activity.

The anti-epileptic, anti-hyperalgesic, and anxiolytic agent gabapentin (1-(aminomethyl)-cyclohexane acetic acid or Neurontin) has previously been shown to bind with high affinity to the alpha2delta subunit of voltage-dependent calcium channels (Gee, N. S. , Brown, J.

Identification of an ATP-sensitive potassium channel current in rat striatal cholinergic interneurones.

1. Whole-cell patch-clamp recordings were made from rat striatal cholinergic interneurones in slices of brain tissue in vitro. In the absence of ATP in the electrode solution, these neurones were found to gradually hyperpolarize through the induction of an outward current at -60 mV.

Heparin, but not other proteoglycans potentiates the mitogenic effects of FGF-2 on mesencephalic precursor cells.

There is increasing evidence that the proteoglycan heparin plays a critical role in the regulation of the activity of FGF-2 by either interacting with its receptor or modifying its stability and functioning. In this study precursor cells were isolated from the rat E14 ventral mesencephalon and cultured as free floating spheres in FGF-2 alone or in combination with heparin or other related proteoglycans, including chondroitin sulfate, keratin sulfate, dermatan sulfate, or hyaluronic acid. Our results show the mitogenic effects of FGF-2 could be potentiated by heparin but not the other four proteoglycans.

Pharmacological studies on the "orphan" opioid receptor in central and peripheral sites.

We have exploited the availability of the "orphan" opioid receptor (referred to here as ORL1) in its "natural state" to investigate the effect of nociceptin (orphanin FQ), the endogenous agonist for the ORL1 receptor in the brain, vas deferens, and myenteric plexus of the small intestine. Nociceptin was a potent agonist in electrically stimulated preparations of vasa deferentia (rat and rabbit) and myenteric plexus (guinea-pig) (IC50 ranging from 18 to 31 nM) and susceptible to enzymic cleavage as addition of a cocktail of peptidase inhibitors to the organ bath produced a leftward shift in concentration-response curves (IC50 ranging from 2.1 to 4.

Identification of novel ligands for the gabapentin binding site on the alpha2delta subunit of a calcium channel and their evaluation as anticonvulsant agents.

As part of a program to investigate the structure-activity relationships of Gabapentin (Neurontin), a number of alkylated analogues were synthesized and evaluated in vitro for binding to the Gabapentin binding site located on the alpha2delta subunit of a calcium channel. A number of other bridged and heterocyclic analogues are also reported along with their in vitro data. Two compounds showing higher affinity than Gabapentin were selected for evaluation in an animal model of epilepsy.

Involvement of the central tachykinin NK1 receptor during maintenance of mechanical hypersensitivity induced by diabetes in the rat.

Our study examines the role of central and peripheral neurokinin1 (NK1) receptors in diabetes-induced mechanical hypersensitivity. Glycine, N, N-dimethyl-, 2-[[2-[[(2-benzofuranylmethoxy)carbonyl]amino]-3-(1H-indol-3-yl)-2 -me thyl-1-oxopropyl] amino]-2-phenylethylester, bisulfate, [R-(R*,R*)] (PD 156982) is a selective NK1 receptor antagonist with nanomolar affinity for the human (IC50 = 1.4 nM) and guinea pig (IC50 = 9.

Evaluation of PD 154075, a tachykinin NK1 receptor antagonist, in a rat model of postoperative pain.

PD 154075 ([(2-benzofuran)-CH2OCO]-(R)-alpha-MeTrp-(S)-NHCH(CH3) Ph) is a selective tachykinin NK1 receptor antagonist. Its effect on development and maintenance of thermal and mechanical hypersensitivity was examined in a rat model of surgical pain. When administered 30 min before surgery, PD 154075 dose-dependently (3-100 mg/kg, s.

The neuroprotective effects of the recombinant interleukin-1 receptor antagonist rhIL-1ra after excitotoxic stimulation with kainic acid and its relationship to the amyloid precursor protein gene.

The cytokine interleukin-1 (IL-1) and its endogenous antagonist (IL-1ra) have important functions in the central nervous system. Recent experimental observations have suggested that recombinant IL-1RA (rhIL-1ra) has neuroprotective properties in ischaemia, excitotoxicity, and trauma. We wished to see what effect rhIL-1ra had on kainic acid-induced neuronal death and to investigate how this might relate to changes in expression of the amyloid precursor protein gene (APP) and glial fibrillary acid protein (GFAP) using in situ hybridization.

Nociceptin hyperpolarises neurones in the rat ventromedial hypothalamus.

Patch-clamp recording techniques were used to examine the effect of nociceptin upon neurones contained in slices from the rat ventromedial hypothalamus (VMH). Bath application of 50-300 nM nociceptin hyperpolarised neurones in a concentration-dependent manner that was not affected by either tetrodotoxin (TTX) or naloxone. In voltage-clamp studies nociceptin induced an outward current at -60mV that had a reversal potential of -100.