This chapter contains section titled: Summary Discussion References

As a Professor Emeritus, all of 3 years standing (having retired in 1983), I welcome our friend and colleague, Vince Dethier, to our ranks on reaching that blissful state of Emeritus. Like many of you, I have enjoyed his friendship and valued his scientific partnership over the years in the study of animal behavior and the chemical senses. My first efforts in that domain began as a graduate student in psychology at Brown University in 1933-1935, and then in England, ultimately at Cambridge, where I completed my Ph.D. dissertation on the electrophysiology of taste in the cat. In that physiology laboratory, as in many others, the cat was a presumed prototypic mammal. As it turned out, it is not a prototypic taster, for it seems not to have developed or retained sensitivity to sugars and other sweeteners that characterizes so many other species of mammals and invertebrates, especially, of course, the fly. I first became acquainted with the fly as a taster by Vince Dethier’s work and in fact met him while he was still at the Hopkins where he began to “know a fly.” Other longtimers there included Curt Richter, who by then “knew the rat,” in particular its specific hungers and self-selection behavior, and Eliot Stellar at the Psychology Department. The Hopkins was a special place at that time in behavioral biology and psychobiology, especially with regard to ingestive behavior and its sensory determinants.

Annals of the New York Academy of SciencesVolume 510, Issue 1 p. 550-553 Multiple Bitter Receptor Sites in Hamstersa CARL PFAFFMANN, CARL PFAFFMANN Laboratory of Neurobiology and Behavior The Rockefeller University New York, New York 10021Search for more papers by this authorM. SCOTT HERNESS, M. SCOTT HERNESS Laboratory of Neurobiology and Behavior The Rockefeller University New York, New York 10021Search for more papers by this author CARL PFAFFMANN, CARL PFAFFMANN Laboratory of Neurobiology and Behavior The Rockefeller University New York, New York 10021Search for more papers by this authorM. SCOTT HERNESS, M. SCOTT HERNESS Laboratory of Neurobiology and Behavior The Rockefeller University New York, New York 10021Search for more papers by this author First published: November 1987 https://doi.org/10.1111/j.1749-6632.1987.tb43622.x a This study was supported in part by a grant from the National Science Foundation, BNS 8111816 and in part by BRSG S07 RR07065 awarded by the Biomedical Grant Program, Division of Research Resources, National Institutes of Health. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume510, Issue1Olfaction and Taste IXNovember 1987Pages 550-553 RelatedInformation

A simple device for precise, noninvasive measurement of stimulus onset time in gustatory research is described. This device utilizes an ultrafast, self-heated, micro-thermistor to sense the cooling effect of the fluid stream that bathes the tongue.

Journal Article Generalization of conditioned taste aversions in hamsters: evidence for multiple bitter receptor sites Get access M. Scott Herness, M. Scott Herness Laboratory of Neurobiology and Behavior, The Rockefeller UniversityNew York, NY 10021, USA Search for other works by this author on: Oxford Academic PubMed Google Scholar Carl Pfaffmann Carl Pfaffmann Laboratory of Neurobiology and Behavior, The Rockefeller UniversityNew York, NY 10021, USA Search for other works by this author on: Oxford Academic PubMed Google Scholar Chemical Senses, Volume 11, Issue 3, August 1986, Pages 347–360, https://doi.org/10.1093/chemse/11.3.347 Published: 01 August 1986 Article history Received: 01 September 1985 Accepted: 01 April 1986 Published: 01 August 1986

The responses of 54 neurons to independent sapid stimulation of 4 taste receptor subpopulations associated with: (1) anterior tongue; (2) nasoincisor ducts; (3) soft palate; and (4) foliate papillae were recorded from the nucleus of the solitary tract (NST) of the rat. Neurons responding to stimulation of receptor subpopulations in the anterior oral cavity (anterior tongue or nasoincisor ducts) were located more rostrally in the NST than neurons responding to stimulation of receptor subpopulations in the posterior oral cavity (soft palate or foliate papillae). Half of the sampled neurons responded exclusively to stimulation of one receptor subpopulation with the remaining neurons responsive to stimulation of two or more receptor subpopulations. The most common pattern of convergence observed was between responses arising from stimulation of the taste buds on the anterior tongue and those associated with the nasoincisor ducts of the hard palate. The sensitivity of NST neurons to anterior tongue and nasoincisor duct stimulation with the 4 standard taste stimuli was determined. When stimulating the anterior tongue, the order of effectiveness was NaCl > HCl > sucrose > quinine hydrochloride (QHCl). When the nasoincisor ducts were tested, however, the order of stimulus effectiveness was strikingly different: sucrose was the best stimulus, followed by HCl, NaCl, and QHCl. If both the anterior tongue and nasoincisor ducts are included, stimulation of taste receptors in the anterior oral cavity of the rat produces good responses to stimuli representing 3 of the 4 classical taste qualities: sweet, salty, and sour.

Recent electrophysiological studies on the iontophoretic application of taste stimuli by weak electric currents using rodents and frogs have produced stimuli which appear to mimic the action of salty, sour and sweet solutions. However, there has been no report of an ionic stimulus which might serve as a bitter iontophoretic probe. Many common bitter stimuli are either uncharged (e.g. quinine, urea) or have mixed quality sensations (e.g. the bitter salts KCl, MgCl2) and therefore are unsuitable. This report investigates the use of four organic anions, all of which are bitter to humans, which may serve as potential bitter stimuli for iontophoretic application to the tongue of the hamster while recording electrophysiologically from its chorda tympani nerve. These anions are m-nitrobenzene sulfonate (NBSA), picrate, cholate and m-nitrobenzoate (NBA). The electrophysiological responses to cathodal polarization via these four anions plus saccharin, an effective cathodal stimulus in the hamster, form the same efficacy series as chemical (i.e. normal sapid) presentations of sodium salts of these anions, i.e. saccharin > NBSA > picrate > NBA > cholate. Behavioral evidence suggests that NBSA is sweet to hamsters while the latter three anions, picrate, NBA and cholate, are bitter. Electrophyiological observations, based on magnitude of response, appear to support these behavioral findings. It was concluded that picrate, NBA and cholate may serve as useful bitter stimulus probes for ionto-phoretic application in the hamster.

This paper describes how the sense of taste controls appetitive and instrumental behavior but also that behavioral methods can reveal how animals perceive taste stimuli. Such methods permit direct comparison of animal psychophysics with sensory electrophysiology in the same organism. The behavioral classification of qualities according to the basic taste stimuli corresponds very well with that derived from the electrophysiological best-stimulus fiber designation in rats and hamsters. Taste stimuli not only elicit preference and aversion behaviors; with appropriate training schedules they can reinforce learning of a variety of instrumental responses. Neurological experiments are described showing that the oro-mimetic components of the sweet preference are organized in the ponto-bulbar lower brainstem and are present in chronic decerebrate mammals. These response patterns, normally present at birth, can be modified in normals by learning but not in chronic decerebrates. The sense of taste is uniquely suited for analyzing the role of sensory stimuli in motivation and learning, in sensory affect and hedonic processes, as well as its sensory physiology.

According to Wundt's schema of sensory affect, increases of stimulus intensity above threshold are felt as increasingly pleasant up to a peak value beyond which pleasantness falls off through indifference to increasing unpleasantness. In psychophysical studies salty and sour taste solutions follow such a biphasic curve. Bitterness is mostly increasingly unpleasant, sweetness is mostly increasingly pleasant to a maximum with little fall off with stimulus intensity. Individual differences among adult subjects reveal some — e.g., sugar dislikers — bitter likers who depart from, or attenuate, these general trends. Studies of one- to three-day-old human neonates show rejection and negative affect for sour and bitter, but only acceptance and pleasant affect for sugar.

Nine groups of rats and 27 groups of hamsters (n = 12/group) each tasted 1 from among 27 different solutions before receiving an ip injection of apomorphine, then were tested for aversions to 4 solutions prototypic of human beings' four taste qualities (S, sucrose; N, NaCl; H, Hcl; Q, quinine hydrochloride). With most of the solutions that are described as sweet by humans employed as a conditional stimulus (CS), the rodents acquired an S aversion (exceptions occurring for some artificial sweeteners). With CSs described as either predominantly salty or sour by humans, the rodents acquired an N aversion in the former case or an H aversion in the latter case; a Q aversion was also acquired with two (including H) of the three CSs described as sour. With most of the CSs described as predominantly bitter or as having a considerable bitter component by humans, the rodents acquired a Q aversion (as well as a weaker H aversion). Considerable parallels among the taste sensations of humans, rats, and hamsters are indicated. Patterns of activity evoked across four classes of peripheral gustatory neurons (those responding best to lingual stimulation with S, N, H, or Q) in rodents when the CSs were applied to the tongue were similar to the patterns of aversions across the four test stimuli for the CSs. This suggests that these four neural channels mediate the sensations evoked by S, N, H, and Q in rats and hamsters, perhaps even in human beings.

Dimethyl disulfide, isolated from estrous hamster vaginal secretion and identified by gas chromatography-mass spectrometry, is an attractant for male hamsters.

(by Carl Pfaffmann) ......... ..... . 284 Conclusions 291 Recent Compilations 291 PERIPHERAL PROCESSES ... 291 Sensory Electrophysiology, Coding, and Behavioral Discrimination 291 Receptor Fields and Single Papilla 299 The Sugar Receptor 301 Taste Preferences and Hedonic Processes ..... 302 CENTRAL ANATOMY AND PHYSIOLOGY OF THE GUSTATORY SYSTEM . ... . .... 305 CENTRAL INVOLVEMENT IN COMPLEX GUSTATORY PHENOMENA .... 312 CONCLUSIONS : 317

A series of aliphatic acids and alcohols was isolated and identified from hamster vaginal discharge. These materials along with a previously identified hamster attractant pheromone, dimethyl disulfide, were assayed in amounts characteristic of a single female collection for their ability to attract normal males and to promote copulatory behavior toward female surrogates. Estrous hamster vaginal discharge attracted normal males and stimulated copulatory attempts toward scented surrogates. Male copulatory behavior was unmodified by: dimethyl disulfide, the aliphatic acids, the aliphatic alcohols or a grand mixture of all these identified components of vaginal discharge. Therefore there must be some, as yet unidentified, material in vaginal discharge which induces normal males to engage in copulatory behavior. Neither the acids nor the alcohols when presented as mixtures had significant effects on male attraction. The attractiveness of a grand mixture of dimethyl disulfide and the series of aliphatic acids and alcohols was comparable to the attractiveness of dimethyl disulfide alone. Thus, the presence of small amounts of dimethyl disulfide can account for much of the ability of whole vaginal discharge to attract males to the odor source even when this compound is assayed in the presence of large amounts of inactive biological odorants.