Hippocampal benzodiazepine receptors in schizophrenia

Benzodiazepine receptor sites were determined by saturable [3H]flunitrazepam binding in hippocampal tissue from schizophrenic and control subjects. No difference in receptor density or affinity between the two groups was observed, indicating that the previously identified GABAergic deficit in the hippocampus in schizophrenia does not apparently lead to up-regulation of these receptor sites. The implications of this finding are discussed.

Pharyngeal pump and esophageal transit

In deglutition the pharynx appears to act as a pump to "inject" boluses into the esophagus. A new method for measuring the velocity profile of the leading edge of a radionuclide bolus has been developed and applied to boluses of different viscosity--water and treacle--in nine normal volunteers. The results show that the more viscous bolus (treacle) acquires a slower initial "injection" velocity (152 mm/sec vs 236 mm/sec) that only propels it over the proximal half of the esophagus. Peristaltic action must drive the bolus over the distal half. With water boluses, however, the higher initial velocity is sufficient to propel a part of the bolus at least to the gastroesophageal junction leaving minimal "work" to be performed by esophageal peristalsis. This confirms the important role of the pharyngeal pump in deglutition. The pump may be the major mechanism for ingestion of nonviscous liquids (water), peristalsis merely being required to "sweep up" what remains in the esophagus.