[Reduction of sensitivity at the level of the membranous urethra after substitutive orthotopic ileal bladder]. / Diminution de la sensibilité au niveau de l'urètre membraneux après vessie iléale orthotopique de substitution.

OBJECTIVE: To determine whether the sensitivity of the membranous urethra is an important factor to obtain continence after ileal bladder replacement. MATERIAL AND METHOD: The sensitivity threshold after electrical stimulation of the membranous urethra by a ring electrode placed on a urethral catheter was measured in 47 men after ileal bladder replacement (postoperative group). The control group consisted of 35 men before radical prostatectomy or cystoprostatectomy. RESULTS: The mean sensitivity threshold of the membranous urethra was 9 +/- 2 mA in the control group and 27 +/- 11 mA in the postoperative group (p < 0.001). The sensitivity threshold of daytime continent and incontinent patients was 24 +/- 9 and 39 +/- 10 mA, respectively (p < 0.001). CONCLUSION: The sensitivity of the membranous urethra decreases in patients after cystoprostatectomy and ileal bladder replacement. The sensitivity of the membranous urethra is better in continent patients than in incontinent patients and therefore appears to be an important factor for continence after ileal bladder replacement.

Urethral sensitivity and the impact on urinary continence in patients with an ileal bladder substitute after cystectomy.

PURPOSE: After cystectomy and ileal bladder substitution, sensitivity in the membranous urethra correlates with postoperative urinary continence. We determine whether sensitivity is decreased only in the most proximal part of the urethra or also more distally in the bulbar urethra, which would give some indication as to which nerves may be injured during radical cystoprostatectomy. MATERIALS AND METHODS: The sensory threshold for electrical stimulation was measured with double ring electrodes in the membranous urethra, and 2.5 cm. distally to it in 41 men after cystectomy and ileal bladder substitution, and in a control group of 29 men. RESULTS: The mean sensory threshold plus or minus standard deviation of the membranous urethra was 9 +/- 2 mA. in the control group compared to 26 +/- 11 mA. in the postoperative group (p <0.001). Mean sensory threshold 2.5 cm. distal to the membranous urethra was 8 +/- 3 versus 9 +/- 3 mA. in the control and postoperative groups, respectively (not significant). Patients with daytime continence had a mean threshold of 22 +/- 8 mA. in the membranous urethra compared to 38 +/- 11 mA. in those who were incontinent (p <0.004) and a threshold of 8 +/- 3 mA. 2.5 cm. distal to the membranous urethra compared to 8 +/- 2 mA. in those who were incontinent (not significant). CONCLUSIONS: After cystectomy and ileal bladder substitution, urethral sensitivity 2.5 cm. distal to the membranous urethra is unaffected by surgery and does not correlate with postoperative continence. In contrast, a decreased sensitivity in the membranous urethra correlates with an increased risk of postoperative incontinence. Preservation of sensitivity in the membranous urethra seems to be an important factor for achieving continence after cystectomy and ileal bladder substitution, and does not seem to be dependent on the extrapelvic portion of the pudendal nerve.

Central muscarinic inhibition of lower urinary tract nociception.

Previous studies indicate cholinergic systems suppress somatic nociception. The present studies determined if cholinergic muscarinic systems suppress visceral nociception, specifically, chemical irritation of the lower urinary tract. Bladders of urethane-anesthetized rats were cannulated through the dome for continuous-infusion cystometrogram recordings. EMG electrodes recorded anal sphincter activity. Infusion of 0.5% acetic acid into the bladder to produce irritation increased bladder activity and anal sphincter activity (i.e. activation of a nociceptive vesicoanal reflex). Oxotremorine (a muscarinic agonist) and (-)butylthio[2.2.2] (a mixed muscarinic agonist/antagonist) dose-dependently inhibited vesicoanal reflex activity. This inhibition was antagonized by atropine (a centrally active muscarinic antagonist) but not by scopolamine methylbromide (a peripherally restricted muscarinic antagonist). Physostigmine (a centrally active cholinesterase inhibitor) also dose-dependently inhibited vesicoanal reflex activity in an atropine-sensitive manner, while neostigmine (a peripherally restricted cholinesterase inhibitor) did not. Atropine alone (i.e. administered without prior administration of muscarinic agonist or cholinesterase inhibitor) produced robust but transient (15 min) increases in vesicoanal activity and bladder activity under conditions of acetic acid infusion into the bladder. Under conditions of saline infusion into the bladder, atropine had the opposite effect on bladder activity (i.e. inhibition). These studies indicate that an endogenous cholinergic muscarinic system can be activated by lower urinary tract irritation to suppress visceral nociception through central nervous system mechanisms.

Decreased sensitivity in the membranous urethra after orthotopic ileal bladder substitute.

PURPOSE: The effect of cystoprostatectomy with orthotopic substitution on membranous urethral sensation and subsequent urinary continence is unknown. We determined the sensory threshold for electrical stimulation of the membranous urethra and correlated it with continence, nerve sparing surgical technique and potency. MATERIALS AND METHODS: The sensory threshold was measured in a control group of 35 men before radical prostatectomy or cystoprostatectomy and in 47 men after cystoprostatectomy and ileal bladder substitution. RESULTS: The sensory threshold of the membranous urethra was 9+/-2 in the control group compared to 27+/-11 mA. in the postoperative group (p<0.001). Patients with daytime continence had a threshold of 24+/-9 compared to 39+/-10 mA. in incontinent patients (p<0.001). We were unable to show any correlation between the sensory threshold in patients with (25+/-10 mA.) and without (31+/-11 mA.) attempted nerve sparing surgery (p = 0.1) nor between potent (25+/-12 mA.) and impotent (27+/-11 mA.) patients (p = 0.4). CONCLUSIONS: Sensitivity in the membranous urethra decreased in patients after cystoprostatectomy and ileal bladder substitution. Urethral sensitivity in the sphincter area was better in continent than incontinent patients. Since we were unable to find any correlation between the sensory threshold and nerve sparing surgery or potency, it may be assumed that at least part of the sensory fibers to the membranous urethra pass through the pudendal nerve and/or the intrapelvic extrapudendal nerve fibers.

Extrinsic innervation of the cat prostate gland: a combined tracing and immunohistochemical study.

PURPOSE: The purpose of the present study was to determine the peripheral neural pathways, spinal distribution, sizes, and peptide transmitter content of primary afferent and autonomic efferent neurons that innervate the prostate gland. METHODS: Retrograde transport of the fluorescent dye "fast blue" (injected into the prostate gland) was combined with neurotransmitter immunohistochemistry. Lesions of the pelvic and pudendal nerve were used to determine the peripheral neural pathways. RESULTS: The majority of the afferent innervation arose from the sacral dorsal root ganglia (DRG) and was equally comprised of small, substance P- and calcitonin gene-related peptide-immunoreactive (IR) neurons and large, non-IR neurons. The majority (70%) of the afferent axons traversed the pelvic nerve with the remainder traversing the pudendal nerve. Fewer afferent neurons were located in lumbar DRG; nearly all of these were small, peptidergic neurons. Efferent autonomic neurons were located in the inferior mesenteric ganglia (IMG), sympathetic chain ganglia (SCG), and pelvic plexus ganglia (PPG). Nearly all efferent neurons in the IMG and SCG, but only 2/3 of the PPG neurons, contained dopamine-beta-hydroxylase. Substantial neuropeptide Y innervation was derived from the SCG but not the IMG or PPG. CONCLUSIONS: First, clinical reports suggested that sensory innervation of the prostate would be purely nociceptive in nature (implied by small, peptide-IR neurons). However, the present study suggests that there may also be a substantial, presumably non-nociceptive, afferent innervation (implied by findings of large, non-IR neurons). Second, 3 sources of autonomic efferent innervation exist, each being different in the distribution of transmitter phenotypes. Understanding the physiological role of putative non-nociceptive primary afferent neurons, and the differential roles of the various autonomic neurons, is likely to be important in developing therapies for the treatment of prostatic diseases, such as benign prostatic hyperplasia and prostatodynia.

Antireflux nipples or afferent tubular segments in 70 patients with ileal low pressure bladder substitutes: long-term results of a prospective randomized trial.

PURPOSE: Intestinal low pressure orthotopic bladder substitutes have no major coordinated contractions during micturition. Therefore, the importance and type of reflux prevention were assessed in a prospective randomized study. MATERIALS AND METHODS: A total of 70 patients with an ileal low pressure bladder substitute was randomized to receive a nipple valve or an isoperistaltic afferent ileal tubular segment for reflux prevention. RESULTS: After median observation times of 57 and 45 months, respectively, the results regarding functional reservoir capacity, incidence of infected urine, urinary continence, voiding habits and serum electrolytes, urea and creatinine were similar in both groups. Severe upper tract dilatation due to ureteroileal or nipple stenosis occurred in 9 of 67 evaluable reno-ureteral units (13.5%) in patients with antireflux nipples and in 2 of 69 (3%) in patients with an afferent tubular segment. This difference in favor of the latter cases is significant (Fisher's exact test p < 0.03). Video urodynamics did not show reflux of contrast medium during voiding in either group. A simultaneous intravesical, intra-abdominal and intrapelvic pressure increase was noted during the Valsalva maneuver. CONCLUSIONS: While long-term upper tract preservation by an afferent tubular ileal segment must be confirmed in larger patient series with longer followup, our results indicate that reflux prevention in patients with orthotopic low pressure bladder substitutes is not a major concern and does not justify the use of antireflux mechanisms with a high complication rate.

Summary of 10 years' experience with an ileal low-pressure bladder substitute combined with an afferent tubular isoperistaltic segment.

We report on 10 years of experience with an ileal low-pressure bladder substitute combined with an afferent tubular segment following cystectomy in 100 consecutive men. The median follow-up period was 30 months (range 3-108 months), with a 2.5-year minimum in survivors. A total of 42 patients died, 33 of these dying of bladder cancer. The early complication rate was 11%, including 2 deaths due to postoperative sepsis. In all, 14 patients required reoperation for late complications. The reservoir's median functional capacity increased to 500 ml at 12 months and was paralleled by improving continence: 92% by day (after 1 year) and 80% by night (after 2 years). Four ureteric strictures occurred. No coordinated, isolated pressure rise developed in the reservoir during voiding, which was accomplished by pelvic floor relaxation with abdominal straining, if necessary. Raised intraabdominal pressure acted equally on the reservoir and ureters, preventing reflux during voiding. This technique is straightforward, allows radical cancer surgery, and protects the upper tract. The favorable functional results are comparable with those achieved by similar techniques, but meticulous follow-up is essential.

Experience in 100 patients with an ileal low pressure bladder substitute combined with an afferent tubular isoperistaltic segment.

Between April 1985 and April 1993, 100 consecutive men underwent lower urinary tract reconstruction after cystectomy. An ileal low pressure reservoir using the Goodwin cup-patch principle was combined with an afferent ileal tubular segment. The early complication rate was 11%, including 2 postoperative deaths due to septicemia. After a median followup of 27 months (range 3 to 96) 14 patients required surgery for late complications (intestinal obstruction, urethral stricture or tumor recurrence, hernia or ureteral stenosis). A total of 32 patients died of metastatic bladder cancer and 7 died of other causes. The functional capacity of the bladder substitute was increased to the desired 450 to 500 ml. after 3 to 12 months, which was paralleled by improving urinary continence. After 1 year 92% of the patients were continent by day and after 2 years 80% were continent at night. Upper tract surveillance with excretory urography, renal ultrasound and serum creatinine estimation has shown 4 left ureteral strictures but not significant upper tract deterioration or ureteral recurrence. Significant reflux was not observed during video urodynamics unless the reservoir was overfilled. During voiding, by outlet relaxation and straining if necessary, the intra-abdominal pressure increase with straining acted equally on the reservoir and ureters. Therefore, unlike voiding with a normal bladder, no isolated intravesical pressure increase occurred and, thus, there was no reflux from the reservoir. The combination of an ileal low pressure reservoir with an afferent isoperistaltic ileal segment and an open end-to-side ureteroileal anastomosis allows for radical cancer surgery with resection of the ureters where they cross the iliac vessels and minimizes the risk of ureteral stenosis. The unidirectional peristalsis of the ureters and the afferent tubular ileal segment seem to protect the upper urinary tract sufficiently. The surgical technique is straightforward and allows for later conversion to an ileal conduit if necessary. The functional results of the bladder substitute are comparable to other similar reservoir techniques, provided that the patients are carefully selected, well rehabilitated and meticulously followed.

Structural analysis of inositol monophosphatase complexes with substrates.

The structures of ternary complexes of human inositol monophosphatase with inhibitory Gd3+ and either D- or L-myo-inositol 1-phosphate have been determined to 2.2-2.3 A resolution using X-ray crystallography. Substrate and metal are bound identically in each active site of the phosphatase dimer. The substrate is present at full occupancy, while the metal is present at only 35% occupancy, suggesting that Li+ from the crystallization solvent partially replaces Gd3+ upon substrate binding. The phosphate groups of both substrates interact with the phosphatase in the same manner with one phosphate oxygen bound to the octahedrally coordinated active site metal and another oxygen forming hydrogen bonds with the amide groups of residues 94 and 95. The active site orientations of the inositol rings of D- and L-myo-inositol 1-phosphate differ by rotation of nearly 60 degrees about the phosphate ester bond. Each substrate utilizes the same key residues (Asp 93, Ala 196, Glu 213, and Asp 220) to form the same number of hydrogen bonds with the enzyme. Mutagenesis experiments confirm the interaction of Glu 213 with the inositol ring and suggest that interactions with Ser 165 may develop during the transition state. The structural data suggest that the active site nucleophile is a metal-bound water that is activated by interaction with Glu 70 and Thr 95. Expulsion of the ester oxygen appears to be promoted by three aspartate residues acting together (90, 93, and 220), either to donate a proton to the leaving group or to form another metal binding site from which a second Mg2+ coordinates the leaving group during the transition state.

Structural studies of metal binding by inositol monophosphatase: evidence for two-metal ion catalysis.

The structure of inositol monophosphatase has been determined to 2.60 A resolution in complexes with Mn2+ and with Mn2+ and phosphate. In the Mn2+ complex, three metal cations and one Cl were bound in the active site on each of the two subunits of the enzyme. Ligands to the three metals include the side chains of Glu 70, Asp 90, Asp 93, and Asp 220, t he carbonyl group of Ile 92, several solvent molecules and the chloride, which is a ligand to each of the cations. When phosphate is soaked into these Mn2+ cocrystals, one of the three Mn2+ ions is expelled from the active site, leaving metal ions with octahedral and tetrahedral coordination geometry. In addition, the structure of apoinositol monophosphatase was determined to 2.5 A resolution. Residues 70-75, a two-turn helical segment which is involved in metal coordination, moves away from the metal binding site by 2-3 A in the absence of cations. Residues 30-40, which wrap around the metal binding site and interact with the metal indirectly through solvent molecules and protein ligands to the metal, become disordered in the absence of metal. In various metal complexes, segmental mobility is also observed in the residues which form the metal binding sites. The results of these studies of the interaction of inositol monophosphatase with cations suggest that the enzyme accomplishes phosphate ester hydrolysis using two metal ions, one with octahedral and one with tetrahedral coordination geometry. Broad metal-binding specificity appears to result from extensive flexibility in several of the protein segments which contribute metal ligands, from the presence of alternate metal ligands and from metal coordination spheres which include water molecules.

Facilitatory and inhibitory effects of selective norepinephrine reuptake inhibitors on hypogastric nerve-evoked urethral contractions in the cat: a prominent role of urethral beta-adrenergic receptors.

Tricyclic antidepressants (TCA), such as imipramine, are well-accepted for the treatment of urinary incontinence and enuresis, but their mechanism of action remains undefined due to their multiple pharmacological actions. To explore only the contribution imparted by sympathomimetic effects on the urethra by norepinephrine (NE) reuptake inhibition, two selective NE reuptake inhibitors (nisoxetine and tomoxetine) that possess no antimuscarinic or serotonergic properties were examined for their effects on sympathetic hypogastric nerve (HgN) evoked urethral contractions in chloralose anesthetized cats. Under control conditions, HgN stimulation produced a biphasic response composed of a consistent initial contraction that was prazosin- (alpha adrenergic antagonist) sensitive, followed by a more variable relaxation that was propranolol- (beta adrenergic antagonist) sensitive. Unexpectedly, nisoxetine (0.03 to 1.0 mg./kg. intravenously, n = 6) and tomoxetine (0.3 to 3 mg./kg. intravenously, n = 3) produced decreases (about 50% to 60% of control) in HgN-evoked contractions. These inhibitory effects of the reuptake inhibitors were reversed by propranolol. In cats that were pretreated with propranolol, nisoxetine produced a significant increase in HgN-evoked contractions. In conclusion, these results indicate that inhibition of NE reuptake into the sympathetic nerve terminal produces a relative increase in the activation of beta adrenergic receptors compared with alpha adrenergic receptors in the urethra. This increased beta receptor stimulation might be due to a greater diffusion of NE away from the neuro-effector junction to extrajunctional sites following blockade of junctional reuptake. These findings should highlight the importance of urethral beta adrenergic receptors, which is not well-recognized in the literature.

The NMR structure of the inhibited catalytic domain of human stromelysin-1.

The three-dimensional structure of the catalytic domain of stromelysin-1 complexed with an N-carboxyl alkyl inhibitor has been determined by NMR methods. The global fold consists of three helices, a five stranded beta-sheet and a methionine located in a turn near the catalytic histidines, classifying stromelysin-1 as a metzincin. Stromelysin-1 is unique in having two independent zinc binding sites: a catalytic site and a structural site. The inhibitor binds in an extended conformation. The S1' subsite is a deep hydrophobic pocket, whereas S2' appears shallow and S3' open.

Positions of His-64 and a bound water in human carbonic anhydrase II upon binding three structurally related inhibitors.

The 3-dimensional structure of human carbonic anhydrase II (HCAII; EC 4.2.1.1) complexed with 3 structurally related inhibitors, 1a, 1b, and 1c, has been determined by X-ray crystallographic methods. The 3 inhibitors (1a = C8H12N2O4S3) vary only in the length of the substituent on the 4-amino group: 1a, proton; 1b, methyl; and 1c, ethyl. The binding constants (Ki's) for 1a, 1b, and 1c to HCAII are 1.52, 1.88, and 0.37 nM, respectively. These structures were solved to learn if any structural cause could be found for the difference in binding. In the complex with inhibitors 1a and 1b, electron density can be observed for His-64 and a bound water molecule in the native positions. When inhibitor 1c is bound, the side chain attached to the 4-amino group is positioned so that His-64 can only occupy the alternate position and the bound water is absent. While a variety of factors contribute to the observed binding constants, the major reason 1c binds tighter to HCAII than does 1a or 1b appears to be entropy: the increase in entropy when the bound water molecule is released contributes to the increase in binding and overcomes the small penalty for putting the His-64 side chain in a higher energy state.

Secondary structure and zinc ligation of human recombinant short-form stromelysin by multidimensional heteronuclear NMR.

Stromelysin-1, a member of the matrix metalloendoprotease family, is a zinc protease involved in the degradation of connective tissue in the extracellular matrix. As a step toward determining the structure of this protein, multidimensional heteronuclear NMR experiments have been applied to an inhibited truncated form of human stromelysin-1. Extensive 1H, 13C, and 15N sequential assignments have been obtained with a combination of three- and four-dimensional experiments. On the basis of sequential and short-range NOEs and 13C alpha chemical shifts, two helices have been delineated, spanning residues Asp-111 to Val-127 and Leu-195 to Ser-206. A third helix spanning residues Asp-238 to Gly-247 is characterized by sequential NOEs and 13C alpha chemical shifts, but not short-range NOEs. The lack of the latter NOEs suggests that this helix is either distorted or mobile. Similarly, sequential and interstrand NOEs and 13C alpha chemical shifts characterize a four-stranded beta-sheet with three parallel strands (Arg-100 to Ile-101, Ile-142 to Ala-147, Asp-177 to Asp-181) and one antiparallel strand (Ala-165 to Tyr-168). Two zinc sites have been identified in stromelysin [Salowe et al. (1992) Biochemistry 31, 4535-4540]. The NMR spectral properties, including chemical shift, pH dependence, and proton coupling of the imidazole nitrogens of six histidine residues (151, 166, 179, 201, 205, and 211), invariant in the matrix metalloendoprotease family, suggest that these residues are zinc ligands. NOE data indicate that these histidines form two clusters: one ligates the catalytic zinc (His-201, -205, and -211), and the other ligates a structural zinc (His-151, -166, and -179). Heteronuclear multiple quantum correlated spectra and specific labeling experiments indicate His-151, -179, -201, -205, and -211 are in the N delta 1H tautomer and His-166 is in the N epsilon 2H tautomer.

Urodynamic and clinical aspects of ileal low pressure bladder substitutes.

Twenty-three patients with an ileal bladder substitute formed after cystectomy for invasive bladder cancer were evaluated clinically and urodynamically between 3 and 38 months post-operatively. The urodynamic measurements were compared with the clinical findings. After re-education of the patients' voiding habits the mean voiding volumes of the bladder substitutes stabilised 6-9 months post-operatively at 350 ml. The frequency of micturition was 3 to 5 times during the day and once or twice at night. The maximum functional capacity (maximum voiding volume) was about 490 ml. Ninety-one per cent of the patients were continent during the day 18 months after the operation and 82% were continent during the night. Micturition was problem-free with an average maximum flow of 25 ml/s and an average micturition time of 50 s. The mean voiding volume of ileal bladder substitutes was 50% of the measured cystometric capacity; the maximum functional capacity (= max. micturition volume) was 80% of the cystometric capacity. The average basal pressure was < 20 cm H2O from the third post-operative month onwards. Eleven of the 23 patients had contractions in the bladder substitute (average at 30 cm H2O) at 55-76% of the maximum cystometric capacity or at approximately 90% of the maximum functional capacity. Such spike waves had no clinical or radiological consequences. If the patients were shown how to increase the functional capacity of a reservoir made from only 40 cm of ileum, the clinical results were excellent.

Reactions of C-terminal omega-amino acid residues in liquid hydrogen fluoride.

The benzyl-ester bond linking the C-terminal delta-aminovaleric acid residue of a peptide to a polymeric support was cleaved with liquid hydrogen fluoride in the presence of anisole, added as scavenger. Instead of the expected peptide with a free carboxyl group at the C-terminus, a peptide terminating in a ketone derivative was obtained. The unusual extent of this known side-reaction was attributed to the effect of the distance between the amino group and the carboxyl group in the C-terminal residue. The results of model experiments corroborated this view.

FK-506-binding protein: three-dimensional structure of the complex with the antagonist L-685,818.

L-685,818 differs only slightly in structure from the immunosuppressive drug FK-506, and both compounds bind with comparable affinity to the 12-kDa FK-506-binding protein (FKBP12), the major intracellular receptor for the drug. Despite these similarities, L-685,818 is a potent antagonist of both the immunosuppressive and toxic effects of the drug. Here, we present a structural analysis of this problem. Although FK-506 and L-685,818 differ greatly in pharmacology, we have found that the three-dimensional structures of their complexes with FKBP12 are essentially identical. Approximately half of each ligand is in contact with the receptor protein, and half is exposed to solvent; the exposed region includes the two sites where the compounds differ. These results indicate that the profound differences in the pharmacology of these two compounds are not caused by any difference in their interaction with FKBP12. Rather, these effects arise because relatively minor changes in the exposed part of a bound ligand have a strong effect on how FKBP12-ligand complexes interact with calcineurin, their putative intracellular target. In addition, FK-506 complexes with FKBP12 proteins from several species all inhibit mammalian calcineurin. Analysis of the three-dimensional structure of the complex with respect to residues conserved among these proteins suggests a small number of surface residues near the bound ligands that may play a critical role in interactions between the protein-drug complex and calcineurin.

Structure of inositol monophosphatase, the putative target of lithium therapy.

Inositol monophosphatase (EC 3.1.3.25), the putative molecular site of action of lithium therapy for manic-depressive illness, plays a key role in the phosphatidylinositol signaling pathway by catalyzing the hydrolysis of inositol monophosphates. To provide a structural basis from which to design better therapeutic agents for manic-depressive illness, the structure of human inositol monophosphatase has been determined to 2.1-A resolution by using x-ray crystallography. The enzyme exists as a dimer of identical subunits, each folded into a five-layered sandwich of three pairs of alpha-helices and two beta-sheets. Sulfate and an inhibitory lanthanide cation (Gd3+) are bound at identical sites on each subunit and establish the positions of the active sites. Each site is located in a large hydrophilic cavern that is at the base of the two central helices where several segments of secondary structure intersect. Comparison of the phosphatase aligned sequences of several diverse genes with the phosphatase structure suggests that the products of these genes and the phosphatase form a structural family with a conserved metal binding site.

New isomeric classes of topically active ocular hypotensive carbonic anhydrase inhibitors: 5-substituted thieno[2,3-b]thiophene-2-sulfonamides and 5-substituted thieno[3,2-b]thiophene-2-sulfonamides.

A series of 5-substituted thieno[2,3-b]- and thieno[3,2-b)- and thieno[3,2-b)thiophene-2-sulfonamides was prepared and evaluated for topical ocular hypotensive activity in glaucoma models. The 5-substituents were varied to maximize both inhibitory potency against carbonic anhydrase and water solubility. At the same time, these substituents were varied in order to obtain compounds with the appropriate pKa to minimize pigment binding in the iris. All of these variables were optimized in the best compound, 5-[[(methoxyethyl)[(methoxyethyl)ethyl] amino]methyl]thieno[2,3-b]thiophene-2-sulfonamide hydrochloride (55).