Frederick H. Meyers

The pharmacology of drug abuse — A novel approach to drug education at San Quentin

A novel and successful undergraduate-level course in pharmacology has been established as part of the drug education program at Californias San Quentin State Prison. The program was designed to create a two-way teaching--learning experience between former drug abusers and their teachers, all of whom were doctoral candidates and post-doctoral scholars in pharmacology at a nearby university medical center. In reviewing the pharmacology of psychoactive drugs, the emphasis was on the principles of drug action in the central nervous system, with additional attention to those factors that contribute a potential for abuse. An attempt was made to present information in a strictly objective and non-prejudical manner. An initial analysis has shown a possible change in attitude among the student-inmates toward drugs of abuse. It is likely that courses following a similar design would be well received and successful in any type of undergraduate program that addresses the subject of drug abuse.

Ureteral Peristaltic Activity

Publisher Summary This chapter discusses the ureteral peristaltic activity. The ureter is a muscular tube interposed between two cavities of low pressure, the renal pelvis proximally and the urinary bladder distally. It is responsible for the transport of a variable volume of urine from the pelvis to the bladder. Normal ureteral function has two separate phases, namely, ureteral filling, which is entirely passive, and ureteral emptying, which is entirely active. A small bolus of urine may stop temporarily in the mid-segment of the ureter. It traverses the upper ureteral segment unaided by peristaltic activity. There is a phase of progressive, passive filling of the upper ureter; after a definite lapse of time, the peristaltic wave appears, signaling the onset of the emptying phase. This biphasic functional activity, involving passive filling and active emptying, or transport, can be observed in both the dog and the human. The degree of bladder distention directly influences ureteral activity. This is not because of a rise in intravesical pressure, but because of the fact that with vesical filling and distention, there is a progressive stretching of the trigone.

Central Sympathoplegic and Norepinephrine-Depleting Effects of Antioxidants

Abstract Carbon disulfide (CS2), tetraethyl lead (TEL), tetraethyl tin (TeET), dithiothreitol (DTT), and gossypol acetic acid (GAA) significantly decreased brain norepinephrine (NE) in rats. The central dopamine (DA) increased after ip administration of CS2, TEL, and DTT, but decreased after TeET and GAA. The brain serotonin decreased only after TeET. Two doses of DTT decreased the NE longer than one dose (24 vs 2 hr) but did not increase DA. L-DOPA, given SC with DTT, delayed the decrease in NE by 24 hr. The similar behavioral and autonomic effects of each of these compounds suggest a central sympatholytic effect and an antipsychotic type of sedation and rigidity. A possible mechanism is reversible inhibition of dopamine β-hydroxylase through the reduction of the copper ion of the enzyme. Each of these reducing agents, together with the boranes previously studied, has similar behavioral and autonomic effects and a common effect on NE concentration, suggesting that the agents act through a physicochemical property rather than by combination with a cellular component. These data have applications to the toxicity of the single agents. They also provide an index of activity, previously lacking, of systemic antoxidant effect.

Neurophysiological Theory of Ureteral Function

Publisher Summary This chapter discusses the neurophysiological theory of ureteral function. All ureteral changes that may develop later in the course of the disease are secondary to bladder dysfunction and are not primarily caused by the effect of the neurogenic deficit on the ureter. Experiments give evidence for the presence of adrenergic and cholinergic receptors in the ureter that are responsive to both endogenous and exogenous mediators. Ureteral contraction waves usually involve a relatively long segment rather than one spot at a time. In the absence of urine flow distal to complete obstruction, as after nephrectomy, there are no contraction waves. Ureteral dyskynesia in functional ureteral obstruction is the only lesion that was thought to be because of a neurogenic deficit with lack of ganglion cells, as is seen in Hirschsprung disease.

36 – Ureteral Plethysmography

Publisher Summary This chapter focuses on the ureteral plethysmography. The usual air- or fluid-filled plethysmograph cannot be applied to the ureter because sealing the plethysmograph may also occlude the ureter. The device, which encircles the ureter, consists of a length of thin-walled rubber tubing contained within a hollow plastic ring. The inner wall of the plastic ring contains an open groove, within which the very slightly inflated rubber tube is partly embedded. The partly exposed surface of the balloon comes in contact with the outer surface of the ureter. Changes in pressure recorded by connecting the tube to a transducer reflect changes in ureteral volume.