Axonal growth towards Xenopus skin in vitro is mediated by matrix metalloproteinase activity.

We have previously demonstrated that the growth of peripheral nervous system axons is strongly attracted towards limb buds and skin explants in vitro. Here, we show that directed axonal growth towards skin explants of Xenopus laevis in matrigel is associated with expression of matrix metalloproteinase (MMP)-18 and also other MMPs, and that this long-range neurotropic activity is inhibited by the broad-spectrum MMP inhibitors BB-94 and GM6001. We also show that forced expression of MMP-18 in COS-7 cell aggregates enhances axonal growth from Xenopus dorsal root ganglia explants.

Impaired axonal regeneration by isolectin B4-binding dorsal root ganglion neurons in vitro.

The subpopulation of dorsal root ganglion (DRG) neurons recognized by Griffonia simplicifolia isolectin B4 (IB4) differ from other neurons by expressing receptors for glial cell line-derived neurotrophic factor (GDNF) rather than neurotrophins. Additionally, IB4-labeled neurons do not express the laminin receptor, alpha7-integrin (Gardiner et al., 2005), necessary for optimal axonal regeneration in the peripheral nervous system.

Effective gene delivery to adult neurons by a modified form of electroporation.

Non-viral methods of transfection of cDNAs into adult neurons and other post-mitotic cells are generally very inefficient. However, the recent development of Nucleofector technology developed by Amaxa Biosystems allows direct delivery of cDNAs into the nucleus, enabling transfection of non-dividing cells. In this study, we describe a reliable method for culturing large numbers of retinal cells from adult rats and using Nucleofection, we were able to transfect cDNA-encoding GFP (jellyfish green fluorescent protein) into retinal ganglion cells (RGCs) with relatively high efficiency (up to 28%).

Neurotrophin-independent attraction of growing sensory and motor axons towards developing Xenopus limb buds in vitro.

The mechanisms for directing axons to their targets in developing limbs remain largely unknown though recent studies in mice have demonstrated the importance of neurotrophins in this process. We now report that in co-cultures of larval Xenopus laevis limb buds with spinal cords and dorsal root ganglia of Xenopus and axolotl (Ambystoma mexicanum) axons grow directly to the limb buds over distances of up to 800 microm and in particular to sheets of epidermal cells which migrate away from the limb buds and also tail segments in culture. This directed axonal growth persists in the presence of trk-IgG chimeras, which sequester neurotrophins, and k252a, which blocks their actions mediated via trk receptors.

Pharmacological characterization of pre- and postsynaptic prostanoid receptors in pig gastric fundus.

This study characterized the subtype of prostanoid receptors on the cholinergic neurones and smooth muscle cells in circularly oriented muscle strips of the pig gastric fundus. Tissues were electrically stimulated (40 V, 4 Hz, 0.25 ms, 2 min) to induce tritium outflow after incubation with [3H]-choline.

Characterization of pre- and postsynaptic muscarinic receptors in circular muscle of pig gastric fundus.

1. This study investigated the subtype of muscarinic receptors on the cholinergic neurones and smooth muscle in the circular muscle of the pig gastric fundus. 2.

Presynaptic modulation of cholinergic neurotransmission in the human proximal stomach.

1. This study investigates whether the cholinergic neurones, innervating the human proximal stomach, can be modulated by nitric oxide (NO) or vasoactive intestinal polypeptide (VIP), or via presynaptic muscarinic, alpha(2)- or 5-hydroxytryptamine(4) (5-HT(4)-) receptors. 2.