Intracranial Delivery Research Articles

A novel device for chronic intracranial drug delivery via microdialysis

A system is described for chronic intracranial drug administration in the rat using a modified in vivo microdialysis probe coupled to an Alzet model 2002 osmotic minipump. The results presented demonstrate that this system can be used for the chronic administration of quinolinic acid with minimal non-specific damage. Each pump delivered approximately 225 μl of solution over a period of 19–20 days when tested in vitro. The dialysis units were uniform in function, delivering > 93% of the [ 3H]quinolinic acid initially loaded into the minipump. For in vivo analysis of this apparatus the dose of quinolinic acid tested produced extensive destruction of the striatum. The present system allows reliable drug diffusion over a relatively large area without pressure injection variability. In conclusion, we have developed a simple and inexpensive technique for administration of drugs into brain parenchyma with substantial advantages over previously used techniques.

Responsiveness of rat hippocampal place cells to the location of rewarding intracranial self-stimulation delivery

Responsiveness of rat hippocampal place cells to the location of rewarding intracranial self-stimulation delivery

Constant-current source for an electrolytic microinfusion transducer system

A circuit is described herein which provides the different magnitudes of current required when using an electrolytic microinfusion transducer system (EMITS) for intracranial drug delivery. The constant-current source provides for precise regulation of a quiescent current (3–20 μA) in addition to the current needed for infusion (100–500 μA). Analog meters are included which allow continuous monitoring of current and voltage.

Serum prolactin in epilepsy and hysteria.

<h3>ABSTRACT</h3> Adeno-associated viral (AAV) vectors allow for site-specific and time-dependent genetic manipulation of neurons. However, for successful implementation of AAV vectors, major consideration must be given to the selection of viral serotype and route of delivery for efficient gene transfer into the cell type being investigated. Here we compare the transduction pattern of neurons in the somatosensory system following injection of AAV9 or AAV2retro in the parabrachial complex of the midbrain, the spinal cord dorsal horn, the intrathecal space, and the colon. Transduction was evaluated based on Cre-dependent expression of tdTomato in transgenic reporter mice, following delivery of AAV9 or AAV2retro carrying identical constructs that drive the expression of Cre/GFP. The pattern of distribution of tdTomato expression indicated notable differences in the access of the two AAV serotypes to primary afferent neurons via peripheral delivery in the colon and to spinal projections neurons via intracranial delivery within the parabrachial complex. Additionally, our results highlight the superior sensitivity of detection of neuronal transduction based on reporter expression relative to expression of viral products.

An intracranial electrode delivery system for the chronic mouse and bat preparation

The construction of an electrode delivery device is described which facilitates the accurate placement of multiple electrode arrays in the chronic small animal preparation. The device is easily constructed, easily used, and has many features which can be readily modified by individual investigators to serve their own needs. During implantation of the electrodes, the delivery device can be used to stimulate, lesion or to record the EEG activity from discrete neural sites. The electrode array is permanently affixed to the skull by dental acrylic anchored to two cranial screws. The use of a delivery system such as the one described may encourage neurobehavioral research with the mouse, a more easily maintained and economical subject than the standard laboratory rat.