Differential visualization of cholinesterasic neuronal somata and fibers by use of modifications of acetylcholinesterase pharmacohistochemistry.

We modified existing acetylcholinesterase (AChE) histochemical techniques to visualize cholinergic neuronal somata and processes in the same rat brain. The AChE staining procedure of Karnovsky and Roots, combined with diisopropylfluorophosphate (DFP) pre-treatment, have previously allowed visualization of neuronal somata. Fibers have been visualized by nickel-diaminobenzidine (DAB)-hydrogen peroxide histochemical intensification. We combined novel modifications of these techniques to visualize cell bodies and fibers simultaneously. Maximal staining of neuronal somata occurs with a 1:1 dilution of both the Karnovsky-Roots medium and the nickel-DAB solution; diluting the Karnovsky-Roots medium 1:10 and increasing the concentration of the nickel-DAB solution twofold allows visualization of fibers previously unstainable with DFP pre-treatment and the classical AChE protocol. It is now possible to visualize both neuronal somata and fibers in adjacent sections of the same brain, in a quick and inexpensive manner.

Effects of intrathecal and systemic administration of buspirone on genital reflexes and mating behavior in male rats.

Buspirone was studied to determine whether the detailed profile of male sexual behavior observed following treatment with the prototypical 5-HT1A ligand, 8-OH-DPAT, can be generalized to other 5-HT1A agonist drugs. Systemic and intrathecal (IT) routes of administration were compared. Like DPAT, significant reduction in intromission frequency followed IT infusion of buspirone (80-160 micrograms) as did intraperitoneal (IP) injection (1-4 mg/kg). IT doses of 80-160 micrograms and all IP doses significantly reduced ejaculation latency. Intercopulatory interval significantly decreased following IP buspirone but not after IT infusion although there were trends in that direction. All IP doses and 80 micrograms IT significantly shortened the postejaculatory interval. Buspirone inhibited erection and/or ejaculation in the ex copula reflex test. A decrease in percentage of rats displaying erections and ejaculation occurred following either route of administration. Ejaculation was significantly inhibited at the low IT dose of 40 micrograms. We conclude that buspirone affects sexual behavior very much like DPAT or other 5-HT1A drugs, to the extent known. Sexual effects of buspirone were generally similar regardless of route of administration, but the effective doses were clearly lower with IT treatment.