Alexander A. Harper

Learn More
Combining intracellular recording and dye-injection techniques permitted direct correlation of neuronal soma size with peripheral nerve conduction velocity in individual neurones of the L4 dorsal root ganglion (d.r.g.) of the anaesthetized 5-8-week-old rat. The conduction velocities fell into two main groups; those greater than 14 m/s (A alpha and beta(More)
The electrical characteristics of individual rat dorsal root ganglion neurones were studied and related to the peripheral axon conduction velocity and morphological cell type. Neurones were divided into four groups based on the conduction velocity of their peripheral axons (A alpha, 30-55 m/s; A beta, 14-30 m/s; A delta, 2.2-8 m/s and C less than 1.4 m/s).(More)
The electrical characteristics of isolated neonatal rat intracardiac neurons were examined at 22 and 37 degrees C using the perforated-patch whole cell recording technique. The mean resting membrane potential was -52.0 mV at 37 degrees C and exhibited no temperature dependence. Lowering the temperature from 37 to 22 degrees C decreased the mean input(More)
A monoclonal antibody (RT97) against neurofilament protein specifically and exclusively labelled a subpopulation of rat dorsal root ganglion (DRG) neurones. For seven ganglia (L4 and T13) studied quantitatively the frequency distribution histograms of the size of labelled cells could be fitted by a single normal distribution whose parameters were extremely(More)
Interest in the functions of intracellular chloride expanded about twenty years ago but mostly this referred to tissues other than smooth muscle. On the other hand, accumulation of chloride above equilibrium seems to have been recognised more readily in smooth muscle. Experimental data is used to show by calculation that the Donnan equilibrium cannot(More)
The hyperpolarization-activated nonselective cation current, I(h), was investigated in neonatal and adult rat intracardiac neurons. I(h) was observed in all neurons studied and displayed slow time-dependent rectification. I(h) was isolated by blockade with external Cs(+) (2 mM) and was inhibited irreversibly by the bradycardic agent, ZD 7288. Current(More)
UNLABELLED We investigated the effects of L-glutamine (0-20 mM) on cardiac function. The isolated perfused working rat heart (left atrial and aortic pressures of 5 and 70 cm H2O, respectively) was subjected to 20 min of normothermic low-flow ischaemia followed by reperfusion for 35 min. In the absence of glutamine, ischaemia-reperfusion caused an immediate(More)
1. The actions of high hydrostatic pressure (10.4, 20.8 MPa) on the membrane currents of Helix neurones were examined under voltage clamp. 2. High hydrostatic pressure (20.8 MPa) reduced the maximum inward current to 0.78 and the delayed outward current, measured at the inward current reversal potential, to 0.75 of their value at atmospheric pressure. 3.(More)
We charted postnatal changes in the intrinsic electrophysiological properties and synaptic responses of rat intrinsic cardiac ganglion (ICG) neurons. We developed a whole-mount ganglion preparation of the excised right atrial ganglion plexus. Using intracellular recordings and nerve stimulation we tested the hypothesis that substantial transformations in(More)
Pancreozymin in man as in animals appears to act as a specific enzyme stimulant. The preparations of pancreozymin used in these experiments also contain cholecystokinin, which causes the gall bladder to contract, and a smooth muscle stimulant, possibly substance P. The duodenal contents obtained in response to a standard dose of secretin and pancreozymin(More)